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Revision as of 23:01, 2 August 2015 editGlider87 (talk | contribs)753 edits I agree with Fnagaton that this reflects consensus.← Previous edit Latest revision as of 11:21, 4 January 2025 edit undoRavenpuff (talk | contribs)Extended confirmed users, Page movers, Pending changes reviewers, Rollbackers66,505 editsm Centuries and millennia: missing full stop 
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{{Short description|Misplaced Pages project page}}
{{Style-guideline|WP:MOSNUM|MOS:NUM}}
{{Redirect|WP:NUMBERS}}
{{MoS guideline|MOS:NUM|WP:MOSNUM}}
<noinclude>{{pp-move-indef}}</noinclude> <noinclude>{{pp-move-indef}}</noinclude>
{{Style}}<!-- {{Style}}
<!--
-- PLEASE MAKE MINOR CHANGES TO THIS TEXT ALSO TO THE EQUIVALENT TEXT AT MOS. MORE SIGNIFICANT CHANGES, ESPECIALLY TO THE ACTUAL STYLE RECOMMENDATIONS, NEED TO BE FLAGGED AT THE WT:MOS TALK PAGE BEFORE IMPLEMENTATION HERE AND AT MOS, UNLESS THEY INVOLVE SECTIONS HERE THAT HAVE NO EQUIVALENT AT MOS (e.g. GEOGRAPHICAL COORDINATES). --><!-- Please use "quotes" when mentioning units (as opposed to using units) instead of ''italics'' or '''bold''' to avoid confusion concerning their proper formatting. --> PLEASE MAKE MINOR CHANGES TO THIS TEXT ALSO TO THE EQUIVALENT TEXT AT MOS.
MORE SIGNIFICANT CHANGES, ESPECIALLY TO THE ACTUAL STYLE RECOMMENDATIONS, NEED TO BE FLAGGED AT THE WT:MOS TALK PAGE BEFORE IMPLEMENTATION HERE AND AT MOS, UNLESS THEY INVOLVE SECTIONS HERE THAT HAVE NO EQUIVALENT AT MOS (e.g. GEOGRAPHICAL COORDINATES).


FORMATTING: This page makes heavy and very particular use of a lot of specific formatting. To avoid confusion concerning the proper formatting of units, symbols, values, variables, code, etc., please observe the following markup conventions on this page:
This page guides the presentation of numbers, dates, times, measurements, currencies, coordinates, and similar material in articles. Its aim is to promote clarity and cohesion; this is especially important ''within'' an article. The goal is to make the whole encyclopedia easier and more intuitive to use.
- Use {{xt}} to mark up positive examples or required text.
- Use {{!xt}} to mark up negative examples or deprecated items.
- Use {{xtn}} to mark up items that may or may not be applied depending on context.
- Use {{xtg}} to mark up items that are very rarely applied{{snd}}dubious, deprecated, disputed, only used in one context (this template may not be needed on this page but is available).
- Use double quotes to mark up words-as-words, "scare-quoting", and quoted sources, but not for unusual purposes. Italics are used heavily on this page for many other things, so do not use them for words-as-words.
- Use {{em}} to mark up emphasis.
- Reserve plain ''italic'' only for conventional stylistic, non-semantic use of italics (e.g. for titles of major published works, foreign phrases, etc.; see above about words-as-words).
- Use '''bold''' to mark up inline headers.
- Use {{strong}} to mark up strong emphasis (rarely needed; {{em}} will usually suffice).
- Use <code>...</code> (or <code><nowiki>...</nowiki></code> if needed) to mark up code examples, including individual special characters. Do not use <tt>; this element no longer exists in HTML5.
- Use {{var}} to mark up variables and variable input, not {{smallcaps}}, ''...'', or other markup.
- Use {{tlx}} to illustrate or name templates (or use {{tl}} if nested inside <code>...</code>).
- Use <kbd>...</kbd> in running prose to indicate editor input choices for templates (not necessary in actual code examples inside <code>...</code>)
- Use <samp>...</samp> in running prose to indicate example code output that should be monospaced, if the need arises.
- Use spaced en dashes, not run-together em dashes, especially with markup examples, so the dash cannot be confused as being part of the example.
- Use {{crossref}} for cross-references to other sections or pages. This produces consistent formatting, and helps identify cross-references in the code for periodic checking against "advice forking".
- Avoid italicization other than as specified above.
- Avoid {{shy}} in or near examples; should probably only be used inside tables, when width is a concern.
- Do not mark up mention of units and the like outside the context of advice about their use. Example: 'Use {{xtn|m}} for "minute" only where there is no danger of confusion with meter'
.
-->


This page guides the presentation of numbers, dates, times, measurements, currencies, coordinates, and similar items in articles. The aim is to promote clarity, cohesion, and consistency, and to make the encyclopedia easier and more intuitive to use. For numbers, dates, and similar items in Misplaced Pages article titles, see the ] guideline.
Where this manual provides options, consistency should be maintained within an article unless there is a good reason to do otherwise. The ] has ruled that editors should not change an article from one guideline-defined style to another without a substantial reason unrelated to mere choice of style, and that revert-warring over optional styles is unacceptable.<ref>{{section link|Misplaced Pages:Requests for arbitration/Jguk|Principles}}, {{section link|Misplaced Pages:Requests for arbitration/jguk 2|Principles}}, and {{section link|Misplaced Pages:Requests for arbitration/Sortan|Principles}}</ref> If discussion cannot determine which style to use in an article, defer to the style used by the first major contributor.

Where this manual gives options, maintain consistency within an article unless there is a good reason to do otherwise. The ] has ruled that editors should not change an article from one guideline-defined style to another without a substantial reason unrelated to mere choice of style; ] over optional styles is unacceptable.{{efn|1=See Arbitration Committee statements of principles in cases on style-related edit warring in ], ], and ]; and ].}} If discussion fails to resolve the question of which style to use in an article, defer to the style used by the first major contributor.
{{TOC limit|4}} {{TOC limit|4}}


==General notes== ==General notes==
===<span id="ExternException" />Quotations, titles, etc.===
{{see also|WP:MOSQUOTE}}
Quotations, titles of books and articles, and similar "imported" text should be faithfully reproduced, even if they employ formats or units inconsistent with these guidelines or with other formats in the same article. If necessary, clarify via '''', article text, or footnotes.
* It is acceptable to change other date formats in the same article to provide consistency, so long as those changes would otherwise be acceptable.<!-- "to provide consistency" with what? Is this suggesting changing the article to match a quote or quotes?-->


===Quotations, titles, etc.<span id="ExternException"></span>===
===Non-breaking spaces===
Guidance on the use of ]s ("hard spaces"){{mdashb}}<code>&amp;nbsp;</code>, {{tlx|nbsp}}, <code>&amp;thinsp;</code>, {{tlx|thinsp}}{{mdashb}}is given in some sections below; {{tlx|nowrap}} may also be useful in controlling linebreaks in some situations. Not all situations in which hard spaces or {{tlx|nowrap}} may be appropriate are described. For further information see {{section link|Misplaced Pages:Manual of Style|Non-breaking spaces}} and ].


{{see also|Misplaced Pages:Manual of Style#Quotations}}
==Chronological items==
<!-- {{Split section|Manual of Style (time and dates)|discuss=Misplaced Pages Talk:Manual of Style (dates and numbers)#Split proposal}} -->
<!-- Temporarily commented out until a suitable destination is identified on the talk page -->


Quotations, titles of books and articles, and similar "imported" text should be faithfully reproduced, even if they use formats or units inconsistent with these guidelines or with other formats in the same article. If necessary, clarify via , article text, or footnotes.
===<span id="Precise language" />Statements likely to become outdated===
{{Shortcut|WP:DATED|WP:EPHEMERAL}}
{{See also|Misplaced Pages:As of|Misplaced Pages:Manual of Style/Words to watch#Relative time references}}


===Non-breaking spaces===
Except on pages updated regularly (e.g. ]), terms such as {{!xt|now}}, {{!xt|currently}}, {{!xt|to date}}, {{!xt|so far}}, {{!xt|soon}}, and {{!xt|recently}} should usually be avoided in favor of phrases such as {{xt|during the 1990s}} and {{xt|in August 1969}}. For future and current events, use phrases such as {{xt|as of {{CURRENTMONTHNAME}} {{CURRENTYEAR}}}} or {{xt|since the beginning of 2010}} to signal the time-dependence of the information. Or (for example) {{tlc|as of|{{CURRENTYEAR}}}} will produce the text {{xt|{{as of|{{CURRENTYEAR}}}}}} and adds the article to a category flagging it for periodic review.<!--though of course this will never happen--> However, do not replace (for example) {{xt|since the start of 2005}} with {{tlc|as of|2005}} because some information (the ''start'' of 2005) would be lost; advanced features of {{tlf|as of}} such as <code><nowiki>{{as of|2005|alt=since the start of 2005}}</nowiki></code> can be used in such circumstances.


Guidance on the use of ]s ("hard spaces") is given in some sections below, but not all situations in which hard spaces ({{t|nbsp}} or <code>&amp;nbsp;</code>) or {{tlx|nowrap}} may be appropriate are described. {{crossref|For further information see {{section link|Misplaced Pages:Manual of Style|Non-breaking spaces}} and ].}}
Relative-time expressions are acceptable for very long periods, such as geological epochs: {{xt|Humans diverged from other primates long ago, but ]. }}


==Chronological items==
===Time of day===
{{Shortcut|WP:MOSTIME|MOS:TIME}}
Context determines whether the ] or ] clock is used; in both, colons separate hours, minutes and seconds (e.g. {{xt|1:38:09{{nbsp}}pm}} or {{xt|13:38:09}}).
* '''12-hour clock times''' end with dotted or undotted lower-case ''a.m.'' or ''p.m.'', or ''am'' or ''pm'', preceded by a ], e.g. {{xt|2:30{{nbsp}}p.m.}} or {{xt|2:30{{nbsp}}pm}} (''markup:'' <code>2:30{{tl|nbsp}}p.m.</code> or <code>2:30{{tl|nbsp}}pm</code>), not {{!xt|2:30p.m.}} or {{!xt|2:30pm}}. Hours should not have a leading zero (e.g. {{xt|2:30{{nbsp}}p.m.}}, not {{!xt|02:30{{nbsp}}p.m.}}). Usually, use {{xt|noon}} and {{xt|midnight}} rather than {{!xt|12 pm}} and {{!xt|12 am}}; whether ''midnight'' refers to the start or the end of a date should be explicitly specified unless clear from the context.
* '''24-hour clock times''' have no a.m., p.m., noon or midnight suffix. Hours under 10 should have a leading zero (e.g. {{xt|08:15}}). {{xt|00:00}} refers to midnight at the start of a date, {{xt|12:00}} to noon, and {{xt|24:00}} to midnight at the end of a date, but "24" should not be used for the first hour of the next day (e.g. use {{xt|00:10}} for ten minutes after midnight, not {{!xt|24:10}}).


===Statements likely to become outdated===
The numerical elements of times-of-day are figures ({{xt|12:45{{nbsp}}p.m.}}) rather than words ({{!xt|twelve forty-five p.m.}}) though conventional terms such as {{xt|noon}} and {{xt|midnight}} are acceptable (taking care, with the latter, to avoid possible date ambiguity in constructions such as ''midnight on July 17'').


{{Shortcut|MOS:SINCE|MOS:DATED|MOS:CURRENT|MOS:RECENT|MOS:NOW}}
====<span id="timezones" />Time zones====
{{See also|Misplaced Pages:Manual of Style/Words to watch#Relative time references|Misplaced Pages:Updating information|Misplaced Pages:As of}}
{{shortcut|WP:TIMEZONE}}Give dates and times appropriate to the ] where an event took place. For example, the date of the ] should be December{{nbsp}}7, 1941 (Hawaii time/{{zwsp}}date). Give priority to the place at which the event had its most significant effects; for example, if a hacker based in China attacked a Pentagon computer in the US, use the time zone for the Pentagon, where the attack had its effect. In some cases the best solution may be to add the date and time in ] (UTC). For example:
:&nbsp; &bull; &nbsp; {{xt|8{{nbsp}}p.m. ] on January{{nbsp}}15, 2001 (01:00{{nbsp}}UTC, January{{nbsp}}16)}}


Except on pages that are inherently time-sensitive and updated regularly (e.g. ]), terms such as {{!xt|now}}, {{!xt|today}}, {{!xt|currently}}, {{!xt|present}}, {{!xt|to date}}, {{!xt|so far}}, {{!xt|soon}}, {{!xt|upcoming}}, {{!xt|ongoing}}, and {{!xt|recently}} should usually be avoided in favor of phrases such as {{xt|during the 2010s}}, {{xt|since 2010}}, and {{xt|in August 2020}}. Wording can usually be modified to remove the "now" perspective: not {{!xt|she is the current director}} but {{xt|she became director on 1 January {{CURRENTYEAR}}}}; not {{!xt|2010{{ndash}}present}} but {{xt|beginning in 2010}} or {{xt|since 2010}}. Terms likely to go out of date include {{!xt|best known for}}, {{!xt|holds the record for}}, etc.{{efn|See also ].}} For current and future events, use phrases such as {{xt|as of {{CURRENTMONTHNAME}} {{CURRENTYEAR}}}} or {{xt|since the beginning of {{CURRENTYEAR}}}} to signal the time-dependence of the information; use the template {{tl|as of}} (or {{tl|updated}}) in conjunction.
Alternatively, include just the ]:
Relative-time expressions are acceptable for very long periods, such as geological epochs: {{xt|Humans diverged from other primates long ago, but ].}}
:&nbsp; &bull; &nbsp;{{xt|21:00{{nbsp}}] (]) on 27{{nbsp}}July 2012}}


{{anchors|Dates|dates|Years|years|Months|Dates and years|Dates, months and years}}
Rarely, the time zone in which a historical event took place has since changed; for example, China to 1949 was divided into ], whereas all of modern China is ]. Similarly, the term "UTC" is not appropriate for dates before this system was adopted in 1960;<ref>See ''''. BIPM. n.d. Retrieved on 2015-03-05 (UTC). – On page 3: "This coordination began on January 1, 1960, and the resulting time scale began to be called informally 'Coordinated Universal Time.{{'"}}</ref> ] (UT) is the appropriate term for the mean time at the ] when it is unnecessary to specify the precise definition of the time scale. Be sure to show the UTC or offset appropriate to the clock time in use at the time of the event, not the modern time zone, if they differ.
===Dates, months, and years===
{{Redirect|WP:YEAR|WikiProject Years|WP:YEARS}}
{{shortcut|MOS:DATE|MOS:DATEFORMAT|MOS:YEAR}}
* These requirements do not apply to dates in quotations or titles; {{crossref|see {{section link|Misplaced Pages:Manual of Style|Quotations}}}}.
* Special rules apply to citations; {{crossref|see {{section link|Misplaced Pages:Citing sources|Citation style}}}}.
* See also ].


=== <span id="dates" /><span id="Dates and years" /> Dates, months and years === ====Formats<span id="Acceptable date formats"></span><span id="Date formats"></span>====
{{shortcut|MOS:DATEFORMAT}}


These requirements do not apply to dates in quotations or titles; see {{section link|Misplaced Pages:Manual of Style|Quotations}}.
Special rules apply to citations; see {{section link|Misplaced Pages:Citing sources|Citation style}}.

==== <span id="Acceptable date formats" /><span id="years" /><span id="Years" /><span id="Months" /><span id="Date formats" />Formats ====
{| class="wikitable" {| class="wikitable"
|+ Acceptable date formats |+ Acceptable date formats
|- |-
! style="width:40pt;"<!--undersized width specification means actual column width determined by widest word/unbreakable string in the column-->| General use
! width="160pt" | General use
! width="175pt" | {{nowrap|Only where brevity is helpful}} {{small|(refs,<ref>Only certain citation styles use abbreviated date formats. See {{Section link|WP:Citing sources|Citation style}}.</ref> tables, {{nobr|infoboxes, etc.)}} }} ! style="width:40pt;"| {{nowrap|Only in limited situations<br>where brevity is helpful}}{{efn|name=brevity|1=For use in tables, infoboxes, references, etc. Only certain citation styles use abbreviated date formats. By default, Misplaced Pages does not abbreviate dates. ]}}
! Comments<!--no width specification means this column will pick up all remaining horizontal width-->
! Comments
|- |-
| {{xt|2{{nbsp}}August 2001}} | {{xt|2{{nbsp}}September 2001}}
| {{xt|2{{nbsp}}Aug 2001}} | {{xt|2{{nbsp}}Sep 2001}}
| {{anchor|DMYCOMMA|DMY COMMA|dmy comma}} A comma doesn't follow the year unless otherwise required by context: {{unordered list| {{xt|The 5 May 1922 meeting was cancelled.}} | {{xt|Except Jones, who left London on 5 March 1847, every delegate attended the signing.}} }}
|
|- |-
| {{xt|August{{nbsp}}2, 2001}} | {{xt|September{{nbsp}}2, 2001}}
| {{xt|Aug{{nbsp}}2, 2001}} | {{xt|Sep{{nbsp}}2, 2001}}
| A comma follows the year unless followed by other punctuation:<ref>See {{Section link|WP:Manual of Style|Commas}}.</ref> {{ unordered list | {{xt|The weather on September 11, 2001, was clear and warm}} | {{xt|Everyone remembers July{{nbsp}}21, 1969{{mdashb}}when man first landed on the Moon}} }} | {{anchor|MDYCOMMA|MDY COMMA|mdy comma}} A comma follows the year unless ]: {{unordered list| {{xt|The weather on March 12, 2005, was clear and warm.}} | {{xt|Everyone remembers July{{nbsp}}20, 1969{{snd}}when humans first landed on the Moon. }} }}
|- |-
| {{xt|2{{nbsp}}August}} | {{xt|2{{nbsp}}September}}
| {{xt|2{{nbsp}}Aug}} | {{xt|2{{nbsp}}Sep}}
| rowspan=2 | Omit year only where there is no risk of ambiguity: {{ unordered list | {{xt|The 2012 London Olympics ran from 25{{nbsp}}July to 12{{nbsp}}August}} | {{xt|January{{nbsp}}1 is New Year's Day}} }} | rowspan=2 | Omit year only where there is no risk of ambiguity: {{ unordered list | {{xt|The 2012 London Olympics ran from 25{{nbsp}}July to 12{{nbsp}}September.}} | {{xt|January{{nbsp}}1 is New Year's Day.}} }}
|- |-
| {{xt|August{{nbsp}}2}} | {{xt|September{{nbsp}}2}}
| {{xt|Aug{{nbsp}}2}} | {{xt|Sep{{nbsp}}2}}
|- |-
| <small>No equivalent for general use</small> | {{nobr|<small>''No equivalent for {{nobr|general use}}''</small>}}
| {{xt|2001-08-02}} | {{xt|2001-09-02}}
| Use {{nowrap|{{small caps|yyyy-mm-dd}}}} format only with ] dates from 1583 onward.<ref>All-numeric {{small caps|yyyy-mm-dd}} dates might be assumed to follow the ] standard, which mandates the Gregorian calendar. Also, technically all must be four-digit years, but Misplaced Pages is unlikely to ever need to format a far-future date beyond the year 9999.</ref> | Use {{nowrap|{{var|yyyy}}-{{var|mm}}-{{var|dd}}}} format only with ] dates from 1583 onward.{{efn|1=All-numeric {{nowrap|{{var|yyyy}}-{{var|mm}}-{{var|dd}}}} dates might be assumed to follow the ] standard, which mandates the Gregorian calendar. Also, technically all years must have (only) four digits, but Misplaced Pages is unlikely to need to format a date beyond the year 9999 anytime soon.<!--don't astronomers deal with dates in the 5 digits or beyond?-->}}
|-
| {{xt|September 2001}}
| {{xt|Sep 2001}}
|
|} |}


{{shortcut|MOS:UNLINKDATES}}{{anchor|Date autoformatting|Autoformatting and linking|Linking and autoformatting of dates|Things to avoid}}
=====Things to avoid=====
* Dates, years, and other chronological items should be linked only when they are relevant to the subject ''and'' likely to be useful to a reader; this rule does not apply to articles that are explicitly on a chronological item, e.g. ], ] {{crossref|(as discussed at {{section link|Misplaced Pages:Linking|Chronological items}})}}.{{efn|1=The ] is deprecated. This change was made August 24, 2008, on the basis of ]. It was ratified in two December 2008 RfCs: ] and ].}}
{{shortcut|MOS:UNLINKDATES|MOS:BADDATEFORMAT}}{{anchor|Date autoformatting|Autoformatting and linking}}{{anchor|Linking and autoformatting of dates}}
* For issues related to dates in sortable tables, {{crossref|see {{section link|Help:Sortable tables|Configuring the sorting}}}} and {{crossref|{{section link|Help:Sortable tables|Date sorting problems}}}}, or consider using {{nowrap|{{tlx|dts|Nov 1, 2008}}.}}
* An abbreviated month should not be followed by a dot except at the end of a sentence ({{xt|Aug 2}}, not {{!xt|Aug. 2}}).<ref>{{section link|Misplaced Pages talk:Manual of Style/Archive 151|RFC: Month abbreviations}}</ref>
* Phrases such as {{xt|]}} (or {{xt|July{{nbsp}}Fourth}}, but not {{!xt|July{{nbsp}}4th}}), {{xt|]}}, {{xt|]}}, and {{xt|]}} are proper names, to which rules for dates do not apply ({{xt|A typical Fourth of July celebration includes fireworks}}).
* Dates should be linked only when they are germane to the subject, as discussed at {{section link|Misplaced Pages:Linking|Chronological items}}.<ref>The ] is deprecated. This change was made August 24, 2008, on the basis of ]. It was ratified in two December 2008 RfCs ] and ]</ref>
* For issues related to dates in sortable tables, see {{section link|Help:Sorting|Date sorting problems}} or consider using {{nowrap|{{tlx|sort|2008-11-01|1 Nov 2008}}}} or {{nowrap|{{tlx|dts|Nov 1, 2008}}.}}
* Phrases such as {{xt|]}} (or {{xt|July{{nbsp}}Fourth}}, but not {{!xt|July{{nbsp}}4th}}), {{xt|]}}, {{xt|]}} and {{xt|]}} are proper names, to which rules for dates do not apply ({{xt|Any decent Fourth of July celebration includes fireworks}}).


{{anchor|Unacceptable date formats}} {{shortcut|MOS:DATESNO|MOS:BADDATE}}{{anchor|Unacceptable date formats}}
{| class="wikitable" {| class="wikitable"
|+ Unacceptable date formats (except in ]) |+ Unacceptable date formats (except in ])
|- |-
! width="140pt" | ] Acceptable ! style="width:95pt;"| ] Unacceptable
! width="140pt" | ] Unacceptable ! style="width:80pt;"| ] Corrected
! width="420pt" | Comments ! Comments
|- |-
|{{!xt|Sep'''.'''<!--←Bold to make dot more obvious.--> 2}}
| rowspan=4 | {{xt|9{{nbsp}}June}} {{small|''or''}} {{xt|June{{nbsp}}9}}
| {{!xt|9 june}}<br />{{!xt|june 9}} |{{xt|Sep 2}}{{efn|name=brevity}}
|rowspan=2 | Do not add a full stop (period) to an abbreviated month or to the ].{{efn|1=For consensus discussion on abbreviated date formats like "Sep 2", see {{section link|Misplaced Pages talk:Manual of Style/Archive 151|RFC: Month abbreviations}}}}
| Months are capitalized
|- |-
| {{!xt|9th June}}<br />{{!xt|June 9th}}<br />{{nowrap|{{!xt|the 9th of June}}}} | {{!xt|9'''.'''<!--←Bold to make dot more obvious.--> June}}
| rowspan=5 | {{xt|9{{nbsp}}June}} or {{xt|June{{nbsp}}9}}
| Do not use ordinals (''1st'', ''2nd'', ''3rd'', etc.)
|- |-
| {{!xt|9 june}}<br>{{!xt|june 9}}
| {{!xt|9'''.'''<!--<<bold to make dot a smidge more obvious--> June}}
| Months should be capitalized.
| Do not add a dot to the{{nbsp}}day
|- |-
| {{!xt|09 June}}<br />{{!xt|June 09}} | {{!xt|9th June}}<br>{{!xt|June 9th}}<br>{{nowrap|{{!xt|the 9th of June}}}}
| Do not use ] ({{!xt|1st}}, {{!xt|2nd}}, {{!xt|3rd}}, etc.).
| rowspan=2 | Do not "zero-pad" month or day, except in all-numeric {{nowrap|({{small caps|yyyy-mm-dd}}) format}}
|-
|{{!xt|09-06}}<br>{{!xt|06-09}}
| Do not use these formats.
|-
| {{!xt|09 June}}<br>{{!xt|June 09}}
| Do not zero-pad day{{nbsp}}...
|- |-
| rowspan=4| {{xt|2007-04-15}}
| {{!xt|2007-4-15}} | {{!xt|2007-4-15}}
| rowspan=6| {{xt|2007-04-15}}{{efn|name=brevity}}
| ... except in all-numeric {{nowrap|({{var|yyyy}}-{{var|mm}}-{{var|dd}}) format}}, in which month and day are zero-padded to two{{nbsp}}digits.
|- |-
| {{!xt|2007/04/15}} | {{!xt|2007/04/15}}
| Do not use separators other than{{nbsp}}hyphen | Do not use separators other than hyphens.
|-
| {{!xt|20070415}}
| Do not omit hyphens.
|- |-
| {{!xt|07-04-15}} | {{!xt|07-04-15}}
| Do not abbreviate year to two digits | Do not abbreviate year.
|- |-
| {{!xt|15-04-2007}}<br />{{!xt|04-15-2007}}<!-- the specific combination of values "04" and "15" (one below 12, the other above 12) used in these "Unacceptable" examples was chosen to allow there to be a single unambiguous entry in the "Acceptable" column--> | {{!xt|15-04-2007}}<br>{{!xt|04-15-2007}}<br>{{!xt|2007-15-04}}<!--The specific combination of values "04" and "15" (one below 12, the other above 12) used in these "Unacceptable" examples was chosen to allow there to be a single unambiguous entry in the "Acceptable" column.-->
| Do not use {{nowrap|{{small caps|dd-mm-yyyy}}}}, {{nowrap|{{small caps|mm-dd-yyyy}}}} or {{nowrap|{{small caps|yyyy-dd-mm}}}} formats, as they are ambiguous for {{nowrap|some dates<ref>These formats cannot, in general, be distinguished on sight, because there are usages in which {{nowrap|03-04-2007}} represents March{{nbsp}}4, and other usages in which it represents April{{nbsp}}3. In contrast there is no common usage in which {{nowrap|2007-04-03}} represents anything other than April{{nbsp}}3.</ref> }} | Do not use {{nowrap|{{var|dd}}-{{var|mm}}-{{var|yyyy}}}}, {{nowrap|{{var|mm}}-{{var|dd}}-{{var|yyyy}}}} or {{nowrap|{{var|yyyy}}-{{var|dd}}-{{var|mm}}}} formats.{{efn|1=These formats cannot, in general, be distinguished on sight, because there are usages in which ''{{nowrap|05-03-1991}}'' represents March{{nbsp}}5, and other usages in which it represents May{{nbsp}}3. According to ]:<!--lightly and silently edited-->
{{quote|Some years ago an American student I knew at university went into a panic when she received a note informing her that her exams were scheduled to start on 03-05-1991. She went into a severe weekend of cramming (studying for 18+ hours per day), until she was almost hospitalised from exhaustion. Only then did she realise that her exams didn't start on the 5th of March{{snd}}two weeks from the date she got the notice{{snd}}but the 3rd of May.<!-- The problem was a couple of her American friends initially presumed that the date mentioned was read as dd/mm/yy, but when the saw her reaction, then presumed she must be right and began studying like hell also. And her moment of doubt disappeared when she saw them studying like mad, presuming that if they are studying she must be correct in reading the date as mm/dd/yy. The end result was five extremely exhausted and highly embarrassed American students, who were never let forget their mistake by all other students, who teased them unmercifully afterwards.-->}}
In contrast, there is no common usage in which ''{{nowrap|1991-05-03}}'' represents anything other than May{{nbsp}}3.
}}
|- |-
| {{!xt|2007 April 15}}<br>{{!xt|2007 Apr 15}}
| Do not use these formats.<!--the comment doesn't say "Do not put year first" because in yyyy-mm-dd format the year DOES go first-->
|-
| {{!xt|7/2001}}<br>{{!xt|7-2001}}<br>{{!xt|07-2001}}<br>{{!xt|2001-07}}<br>{{!xt|2001 July}}<br>{{!xt|July of 2001}}
| rowspan=2| {{xt|July 2001}} | rowspan=2| {{xt|July 2001}}
| Do not use these{{nbsp}}formats.
| {{!xt|7-2001}}<br />{{!xt|07-2001}}<br />{{!xt|2001-07}}<br />{{!xt|2001 July}}<br />{{!xt|July of 2001}}
| Do not use these{{nbsp}}formats. ({{!xt|2001-07}}, in particular, can be mistaken for the range of {{nobr|years {{nobr|2001{{ndash}}2007}}.)}}
|- |-
| {{!xt|July''',''' 2001}} | {{!xt|July''',''' 2001}}
| rowspan=2| No comma between month and{{nbsp}}year | rowspan=2| No comma between month and{{nbsp}}year.
|- |-
| {{xt|3{{nbsp}}July 2001}}
| {{!xt|3 July''',''' 2001}} | {{!xt|3 July''',''' 2001}}
| {{xt|3{{nbsp}}July 2001}}
|- |-
| {{xt|July{{nbsp}}3''',''' 2001}}
| {{!xt|July 3 2001}} | {{!xt|July 3 2001}}
| {{xt|July{{nbsp}}3''',''' 2001}}
| Comma required between day and{{nbsp}}year
| Comma required between day and{{nbsp}}year.
|- |-
| {{!xt|the{{nbsp}}'''{{'}}'''97 elections}}<br>{{!xt|the{{nbsp}}97 elections}}
| {{xt|{{nowrap|the 1997 elections}}}} | {{xt|{{nowrap|the 1997 elections}}}}
| Do not abbreviate year.
| {{!xt|the{{nbsp}}'''{{'}}'''97 elections}}<br/>{{!xt|the{{nbsp}}97 elections}}
| Do not abbreviate freestanding year
|- |-
| {{xt|Copyright 2002}}
| {{!xt|Copyright MMII}} | {{!xt|Copyright MMII}}
| {{xt|Copyright 2002}}
| ] are not normally used for{{nbsp}}dates
| ] are not normally used for{{nbsp}}dates.
|- |-
| {{!xt|{{nowrap|Two thousand one}}}}
| {{xt|2001}} | {{xt|2001}}
| rowspan=2| Years and days of the month are not normally written in{{nbsp}}words.
| {{!xt|{{nowrap|Two thousand one}}}}
| rowspan=2| Years and days of the month are not normally written in{{nbsp}}words
|- |-
| {{nowrap|{{xt|May{{nbsp}}1}}{{small|'' or ''}}{{xt|1{{nbsp}}May}}}}
| {{!xt|the first of May}}<br>{{!xt|May the first}} | {{!xt|the first of May}}<br>{{!xt|May the first}}
| {{nowrap|{{xt|1{{nbsp}}May}} or {{xt|May{{nbsp}}1}}}}
|- |-
| {{xt|June 622}}
| {{!xt|June 0622}} | {{!xt|June 0622}}
| {{xt|June 622}}
| Do not zero-pad years
| Do not zero-pad years.
|-
| {{!xt|June 2''','''015}}
| {{xt|June 2015}}
| Do not add a comma to a four-digit year.
|- |-
| {{xt|sold in 1995}}
| {{!xt|{{nowrap|sold in the year 1995}}}} | {{!xt|{{nowrap|sold in the year 1995}}}}
| {{xt|sold in 1995}}
| Use "in the year" only where needed for clarity {{nowrap|({{xt|About 1800{{nbsp}}ships arrived in the year 1801}})}}
| Write "the year" only where needed for clarity ({{xt|{{nowrap|About 200 ships}} arrived in {{nowrap|the year 300}}}}).
|} |}


=====Consistency===== =====Consistency=====

{{anchor|Format consistency}} {{anchor|Format consistency}}
{{shortcut|MOS:DATEUNIFY}} {{shortcut|MOS:DATEUNIFY}}
{{unordered list
* '''Dates in article body text''' should all use the same format: {{xt|She fell ill on 25{{nbsp}}June 2005 and died on 28{{nbsp}}June}}, but not {{!xt|She fell ill on 25{{nbsp}}June 2005 and died on June{{nbsp}}28}}.
| '''Dates in article body text'''{{efn|name=body|''Body'' in this context means the main prose of the article, as distinguished from reference citations, tabular data, infoboxes, navigation templates, and metadata such as hatnote templates, etc. Other parts of the Manual of Style may use ''body'' to mean 'the bulk of the article after the lead section', but that is not the meaning here. Misplaced Pages's article leads are not written in a different prose style from the material following them.}} should all use the same format: {{xt|She fell ill on {{nobr|25 June 2005}} and died on {{nobr|28 June}}}}, not {{!xt|She fell ill on {{nobr|25 June 2005}} and died on {{nobr|June 28}}}}.
* '''Publication dates''' in an article's citations should all use the same format, which may be:
| '''Publication dates''' in an article's citations should all use the same format, which may be:{{unordered list
:* the format used in the article body text,
:* an abbreviated format from the ], provided the day and month elements are in the same order as in dates in the article body, or | the format used in the article body text,
| an abbreviated format from the ], provided the day and month elements are in the same order as in dates in the article body
:* the format expected in the ] being used (however, all-numeric date formats other than {{nowrap|{{small caps|yyyy-mm-dd}}}} must still be avoided). | the format expected in the ] being used (but all-numeric date formats other than {{nowrap|{{var|yyyy}}-{{var|mm}}-{{var|dd}}}} must still be avoided).}}
: For example, a single article might contain one, but only one, of: For example, publication dates within a single article might be in one, but only one, of these formats (among others):{{unbulleted list|style=margin-left: 1.5em
:: {{xt|Jones, J. (20{{nbsp}}September 2008)}} | {{xt|Jones, J. (20 September 2008)}}
:: {{xt|Jones, J. (September{{nbsp}}20, 2008)}} | {{xt|Jones, J. (September 20, 2008)}}}}
If an article uses a template such as {{tlx|Use mdy dates}} or {{tlx|Use dmy dates}}, then ] and ] templates automatically render dates ({{para|date}}, {{para|access-date}}, {{para|archive-date}}, etc) in the specified format, regardless of the format they are entered in. (The {{para|cs1-dates}} parameter can be used to fine-tune the generated output, {{crossref|pw=y|see {{section link|Template:Use mdy dates|Auto-formatting citation template dates}}}}.)
:: {{xt|Jones, J. (20{{nbsp}}Sep 2008)}}
| '''Access and archive dates''' in an article's citations should all use the same format, which may be:{{unordered list
: (among other possibilities).
| the format used for publication dates in the article (see above);
* '''Access and archive dates''' in an article's citations should all use the same format, which may be:
:* the format used for publication dates in the article, | the format expected in the citation style adopted in the article; or
| {{nowrap|{{var|yyyy}}-{{var|mm}}-{{var|dd}}}}}}
:* the format expected in the citation style adopted in the article, or
For example, access/archive dates within a single article might be in one, but only one, of these formats (among others):{{unbulleted list|style=margin-left: 1.5em
:* {{nowrap|{{small caps|yyyy-mm-dd}}}}
| {{xt|Jones, J. (September 20, 2008){{nbsp}}... Retrieved February 5, 2009.}}
: For example, a single article might contain either of the following:
:: {{xt|Jones, J. (20{{nbsp}}Sep 2008){{nbsp}}... Retrieved 5{{nbsp}}Feb 2009.}} | {{xt|Jones, J. (20 Sep 2008){{nbsp}}... Retrieved 5 Feb 2009.}}
:: {{xt|Jones, J. (20{{nbsp}}Sep 2008){{nbsp}}... Retrieved 2009-02-05.}} | {{xt|Jones, J. (20 September 2008){{nbsp}}... Retrieved 2009-02-05.}}}}
:When a citation style does not expect differing date formats, it is permissible to normalize publication dates to the article body text date format, and/or access/archive dates to either, with date consistency being preferred. When a citation style does not expect differing date formats, it is permissible to normalize publication dates to the article body text date format, and/or access/archive dates to either, with date consistency being preferred.}}


=====Strong national ties to a topic===== =====Strong national ties to a topic=====

{{shortcut|MOS:DATETIES}} {{shortcut|MOS:DATETIES}}
{{See also|Misplaced Pages:Manual of Style#Strong national ties to a topic}}
* Articles on topics with strong ties to a particular English-speaking country should generally use the date format most commonly used in that nation. For the United States this is, for example, {{xt|July 4, 1976}}; for most other nations it is, for example, {{xt|4 July 1976}}.
* Articles related to Canada may use either format with (as always) consistency within each article.
* In some topic areas the customary format differs from the usual national one: for example, articles on the modern U.S. military use day-before-month, in accordance with U.S. military usage.


Articles on topics with strong ties to a particular English-speaking country (see {{section link|Misplaced Pages:Manual of Style#Strong national ties to a topic}}) should generally use the date format most commonly used in that country.
=====<span id="Retaining the existing format" />Retaining existing format=====
*For the United States this is MDY ({{nobr|{{xt|July 4, 1976}}}})
{{shortcut|MOS:DATERET}}
*For most other English-speaking countries it is DMY ({{nobr|{{xt|4 July 1976}}}}).
{{See also|Misplaced Pages:Manual of Style#Retaining the existing variety|}}
*Articles relating to Canada may use either format with (as always) consistency within each article. {{See below|{{section link||Retaining existing format}}, below}}
*{{shortcut|MOS:MILFORMAT}} However, in certain topic areas, it is customary to use a date format different from the usual national one. For example, articles (including biographical articles) on the modern US military should use DMY dates, in accordance with US military usage.

In articles without strong ties to a particular English-speaking country, the choice of date format and the choice of national variety of English are independent and unrelated.

=====Retaining existing format<span id="Retaining the existing format"></span>=====


{{shortcut|MOS:DATERET|MOS:DATEVAR}}
* If an article has evolved using predominantly one format, the whole article should conform to it, unless there are reasons for changing it based on strong national ties to the topic or consensus on the article's talk page.
{{See also|Misplaced Pages:Manual of Style#Retaining existing styles}}
* The date format chosen by the first major contributor in the early stages of an article should continue to be used, unless there is reason to change it based on strong national ties to the topic or consensus on the article's talk page.
* If an article has evolved using predominantly one date format, this format should be used throughout the article, unless there are reasons for changing it based on the topic's strong ties to a particular English-speaking country, or consensus on the article's talk page.
* The date format chosen in the first major contribution in the early stages of an article (i.e., the first non-stub version) should continue to be used, unless there is reason to change it based on the topic's strong ties to a particular English-speaking country, or consensus on the article's talk page.
* Where an article has shown no clear sign of which format is used, the first person to insert a date is equivalent to "the first major contributor". * Where an article has shown no clear sign of which format is used, the first person to insert a date is equivalent to "the first major contributor".


====<span id="Year numbering systems" /><span id="Eras and other very long periods" />Era style==== ====Era style<span id="Year numbering systems"></span><span id="Eras and other very long periods"></span>====

{{shortcut|WP:ERA|WP:BCE}}
{{Redirect|WP:BCE|the copyediting guide|Misplaced Pages:Basic copyediting}}
* The default ] is the ], a year numbering system also known as the Western Christian era (represented by {{xt|]}}), or the ] (represented by {{xt|]}}).
{{shortcut|MOS:ERA|MOS:BCE}}
** BC and AD are the traditional ways of referring to this era. BCE and CE are common in some scholarly texts and religious writings. Either convention may be appropriate.
* The default ]s are ] ({{xt|BC}} and {{xt|AD}}) and ] ({{xt|BCE}} and {{xt|CE}}). Either convention may be appropriate for use in Misplaced Pages articles depending on the article context. Apply {{section link|Misplaced Pages:Manual of Style|Retaining existing styles}} with regard to changes from one era to the other.
*** Do not change the established era style in an article unless there are reasons specific to its content. Seek consensus on the talk page ''before'' making the change. Open the discussion under a subhead that uses the word "era". Briefly state why the style is inappropriate for the article in question. A personal or categorical preference for one era style over the other is not justification for making a change.
** Use either the BC{{ndash}}AD or the BCE{{ndash}}CE notation consistently within the same article. Exception: do not change ], titles, etc.
*** BCE and CE or BC and AD are written in upper case, unspaced, without periods (full stops), and separated from the year number by a space ({{xt|5{{nbsp}}BC}}, not {{!xt|5BC}}). It is advisable to use a ].
** An article's established era style should not be changed without reasons specific to its content; seek consensus on the talk page first (applying {{section link|Misplaced Pages:Manual of Style|Retaining existing styles}}) by opening a discussion under a heading using the word ''era'', or another similarly expressive heading, and briefly stating why the style should be changed.
*** {{xt|AD}} may appear before or after a year ({{xt|AD{{nbsp}}106}}, {{xt|106{{nbsp}}AD}}); the other abbreviations appear only after ({{xt|106{{nbsp}}CE}}, {{xt|3700{{nbsp}}BCE}}, {{xt|3700{{nbsp}}BC}}).
** BCE and CE or BC and AD are written in upper case, unspaced, without a full stop (period), and separated from the numeric year by a space ({{xt|5{{nbsp}}BC}}, not {{!xt|5BC}}). It is advisable to use a ].
*** In general, do not use CE or AD unless required to avoid ambiguity (e.g. {{xt|The Norman Conquest took place in 1066}} not {{!xt|1066{{nbsp}}CE}} nor {{!xt|AD{{nbsp}}1066}}) or awkwardness ({{xt|January 1, 1{{nbsp}}AD}} not {{!xt|January 1, 1}}). On the other hand, {{xt|] was a philosopher living at the end of the 3rd century AD}} will avoid unnecessary confusion. Also, in {{xt|He did not become king until 55{{nbsp}}CE}} the era marker makes it clear that "55" does not refer to his age. Alternatively, {{xt|He did not become king until the year 55.}}
** AD appears before or after a year ({{xt|AD{{nbsp}}106}}, {{xt|106{{nbsp}}AD}}); BCE, CE, and BC always appear {{em|after}} ({{xt|106{{nbsp}}CE}}, {{xt|3700{{nbsp}}BCE}}, {{xt|3700{{nbsp}}BC}}).
*** Use either the BC{{ndash}}AD or the BCE{{ndash}}CE notation consistently within the same article. Exception: do not change ], titles, etc.
** In general, omit CE or AD, except to avoid ambiguity or awkwardness.
* '''Uncalibrated (bce) radiocarbon dates:''' Some source materials will indicate whether a date is calibrated or not simply by a change in capitalisation; this is often a source of confusion for the unwary reader. Do not give ] (represented by the lower-case ''bce'' unit, occasionally ''bc'' or ''b.c.'' in some sources), except in directly quoted material, and even then include a footnote, a square-bracketed editor's note , or other indication to the reader what the calibrated date is, or at least that the date is uncalibrated. Calibrated and uncalibrated dates can diverge surprisingly widely, and the average reader does not recognise the distinction between ''bce'' and ''BCE'' or ''BC''.
*** Typically, write {{xt|The ] took place in 1066}} not {{!xt|1066{{nbsp}}CE}} or {{!xt|AD{{nbsp}}1066}}.
* '''BP''': In scientific and academic contexts, ] (before present) is often used. This is calibrated from January 1, 1950, not from the date of publication, though the latter introduces an insignificant error when the date is distant or an approximation (18,000{{nbsp}}BP). BP years are given as {{xt|18,000{{nbsp}}BP}} or spelled out as {{xt|18,000{{nbsp}}years before present}} (not {{!xt|18,000{{nbsp}}YBP}}, {{!xt|18,000 before present}}, {{!xt|18,000 years before the present}}, or similar). Do not convert other notations to or from BP unless you are certain of what you are doing. A safer and simpler alternative may be to use {{xt|ya (years ago)}}.
*** But {{xt|] lived at the end of the 3rd century AD}} (not simply {{!xt|at the end of the 3rd century}}) may avoid confusion unless the era is clear from context.
* '''Other era systems''' may be appropriate in an article. In such cases, dates should be followed by a conversion to Dionysian (or vice versa) and the first instance should be linked: "Qasr-al-Khalifa was built in 221{{nbsp}}] (836{{nbsp}}CE)" or "in 836{{nbsp}}AD (221{{nbsp}}])".
*** One- and two-digit years may look more natural with an era marker ({{nobr|{{xt|born in 2 AD}}}} or {{nobr|{{xt|born January 15, 22 CE}}}}, not {{nobr|{{!xt|born in 2}}}} nor {{nobr|{{!xt|January 15, 22}}).}}
** ] follows the Common Era and does not require conversion, but the first instance of a non-positive year should still be linked: {{xt|The March equinox passed into Pisces in ].}}
*** Ranges beginning in BC{{\}}BCE should specify the ending era: write {{nobr|{{xt|450 to 200 BCE}}}} or {{nobr|{{xt|450 BC to 200 BC}}}} or {{nobr|{{xt|450 BCE to 200 CE}}}}, but not {{nobr|{{!xt|450 BCE to 200}}}}. {{see below|]}}
* '''Uncalibrated (BCE) radiocarbon dates:''' ] dates can diverge widely, and some sources distinguish the two only via BCE or BC (for calibrated dates) versus bce or bc (uncalibrated). When feasible, avoid uncalibrated dates except in direct quotations, and even then ideally give the calibrated date in a footnote or square-bracketed note{{snd}}{{xt|}}, or at least indicate the date type{{snd}}{{xt|}}. This also applies to other dating systems in which a calibration distinction is drawn.
* '''BP or YBP''': In scientific and academic contexts, BP (Before Present) or YBP (years Before Present) are often used. (''Present'' in this context by convention refers to January{{nbsp}}1, 1950.) Write {{xt|3000 years{{nbsp}}BP}} or {{xt|3000{{nbsp}}YBP}} or {{xt|3000{{nbsp}}years before present}} but not forms such as {{!xt|3000 before present}} and {{!xt|3000 years before the present}}. If one of the abbreviated forms is used, link to '']'' on first use: {{xt|The Jones artifact was dated to 4000{{nbsp}}], the Smith artifact to 5000 YBP.}}
* {{anchor|Other_era_systems}}'''Other era systems''' may be appropriate in an article. In such cases, dates should be followed by a conversion to Anno Domini or Common Era, and the first instance linked: {{xt|Qasr-al-Khalifa was built in {{nobr|221 ] (836 CE)}}}}, or {{nobr|{{xt|in 836 AD (221 ])}}}}.
** ] is similar to the Common Era. There is no need to follow a year expressed with astronomical year numbering with a conversion to Common Era. The first instance of a non-positive year should still be linked: {{xt|The March equinox passed into Pisces in ].}} (The expressions {{xt|&minus;67}} and {{xt|68{{nbsp}}BCE}} refer to the same year.)<!--I suppose we should say something somewhere about use of &minus in this case-->


====Julian and Gregorian calendars==== ====Julian and Gregorian calendars====

{{shortcut|WP:OSNS|WP:JG}}
{{shortcut|MOS:OSNS|MOS:JG}}
{{see also|Old Style and New Style dates}} {{see also|Old Style and New Style dates}}


A date can be given in any appropriate calendar, as long as it is (at the minimum) given in the ] or the ] or both, as described below. For example, an article on the early ] may give dates in both ] and Julian calendars. Where a calendar other than the Julian or Gregorian is used, the article must make this clear. A date can be given in any appropriate calendar, as long as it is (at the minimum) given in the ] or the ] or both, as described below. For example, an article on the early ] may give dates in both ] and Julian calendars. Where a calendar other than the Julian or Gregorian is used, the article must make this clear.
* Current events are dated using the Gregorian calendar. * Current events are dated using the Gregorian calendar.
* Dates of events in countries using the Gregorian calendar at that time are given in the Gregorian calendar. This includes some of the ], the ] from 14{{nbsp}}September 1752, and Russia from 14{{nbsp}}February 1918 (see ]). * Dates of events in countries using the Gregorian calendar at that time are given in the Gregorian calendar. This includes some of the ], the ] from 14{{nbsp}}September 1752, and Russia from 14{{nbsp}}February 1918 {{crossref|(see ])}}.
* Dates before 15{{nbsp}}October 1582 (when the Gregorian calendar was first adopted in some places) are normally given in the Julian calendar. The Julian day and month should not be converted to the Gregorian calendar, but the start of the ] should be assumed to be 1{{nbsp}}January (see below for more details). * Dates before 15{{nbsp}}October 1582 (when the Gregorian calendar was first adopted in some places) are normally given in the Julian calendar.
* Dates after 4{{nbsp}}October{{nbsp}}1582 in a place where the Julian calendar was observed should be given in the Julian calendar.
* For either the Julian or Gregorian calendars, the beginning of the year should be treated as 1{{nbsp}}January even if a different start-of-year date was observed in the place being discussed.
* Dates for Roman history before 45{{nbsp}}BC are given in the ], which was neither Julian nor Gregorian. When (rarely) the Julian equivalent is certain, it may be included. * Dates for Roman history before 45{{nbsp}}BC are given in the ], which was neither Julian nor Gregorian. When (rarely) the Julian equivalent is certain, it may be included.
* For dates in early Egyptian and Mesopotamian history, Julian or Gregorian equivalents are often uncertain. Follow the consensus of reliable sources, or indicate their divergence. * For dates in early Egyptian and Mesopotamian history, Julian or Gregorian equivalents are often uncertain. Follow the consensus of reliable sources, or indicate their divergence.


The dating method used should follow that used by reliable secondary sources (or if reliable sources disagree, that used most commonly, with an explanatory ]). The dating method used should follow that used by reliable secondary sources (or if reliable sources disagree, that used most commonly, with an explanatory ]). The guidance above is in line with the usage of reliable sources such as '']'',<ref>{{cite encyclopedia | encyclopedia = American National Biography |title = Editorial note | date = 1999 | publisher = Oxford University Press | editor1-last = Garraty | editor1-first = John A. | editor2-last = Carnes | editor2-first = Mark C. | pages = xxi&ndash;xxii}}</ref> '']'', and '']''.{{efn|1=The calendar practices of ''Oxford Dictionary of National Biography'' and ''Encyclopædia Britannica'' can be inferred by looking up the birth and death dates of famous, well-documented individuals.}}


Where it is not obvious that a given date should be given in Julian alone or in Gregorian alone, consider giving both styles, for example by using {{tl|OldStyleDate}}. If a date appears without being specified as Old Style or New Style, tagging that date with {{tl|which calendar?}} will add the page to ] for further attention.
At some places and times, the new year began on a date other than 1{{nbsp}}January. For example, in England and its colonies until 1752, the year began on ], 25{{nbsp}}March; see the ] for other styles. In writing about historical events, however, years should be assumed to have begun on 1{{nbsp}}January (see the example of the execution of Charles I in "]"); if there is reason to use another start-of-year date, this should be noted.


If there is a need to mention ] dates in an article (as in the ]), a footnote should be provided on the first usage, stating whether the ''New Style'' refers to a start of year adjustment or to the Gregorian calendar (it can mean either). If an article contains Julian calendar dates after 4 October 1582 (as in the ]), or if a start-of-year date other than 1 January was in force in the place being discussed, or both, a footnote should be provided on the first usage, explaining the calendar usage adopted for the article. The calendar usage should be compatible with this guideline.


===={{anchor|Date ranges}}Ranges==== ====Ranges<span id="Date ranges"></span>====
{{anchors|Other date ranges|Dates of birth and death}}{{shortcut|MOS:DOB|WP:BORN|WP:OTHERDATE|WP:DATERANGE}} {{anchors|Other date ranges|Dates of birth and death}}
{{shortcut|MOS:DATERANGE|MOS:DOB|MOS:YEARRANGE}}
{{See also|Misplaced Pages:Manual of Style#Number ranges}}
* A pure '''year{{ndash}}year''' range is written (as is any range) using an en dash{{mdashb}}<code>&amp;ndash;</code> or {{tlx|ndash}}{{mdashb}}not a hyphen or slash; this dash is usually ''unspaced'' (that is, with no space on either side); and the range's "end" year is usually abbreviated to two digits:
{{Redirect|MOS:DIED|euphemisms for "died"|Misplaced Pages:Manual of Style/Words to watch#Euphemisms}}
: &nbsp; &bull; &nbsp; {{xt|1881{{ndash}}86}};{{nbsp}} {{xt|1881{{ndash}}92}} (not {{!xt|1881{{ndash}}6}};{{nbsp}} {{nobr|{{!xt|1881{{snd}}86}}}})
* A simple '''year{{ndash}}year''' range is written using an ] (<code>–</code>, <code>&amp;ndash;</code> or {{tlx|ndash}}, or {{tlx|nbnd}} for a non-breaking en dash), not an em dash, hyphen, or slash; this dash is {{em|unspaced}} (that is, with no space on either side); and the end year is usually given in full:
:: {{hanging indent|text=''Markup:'' <code>1881{{t|ndash}}86</code> ''or'' {{nowrap|<code>1881&amp;ndash;86</code>}} }}
** {{xt|1881{{ndash}}1882}};{{nbsp}} {{xt|1881{{ndash}}1886}} (not {{!xt|1881{{ndash}}86}});{{nbsp}} {{xt|1881{{ndash}}1892}} (not {{!xt|1881{{ndash}}92}})
: ''But both years are given in full in the following cases:''
*** ''Markup:'' <code>1881{{tl|ndash}}1882</code> or <code>1881&amp;ndash;1882</code>
:* '''birth{{ndash}}death parentheticals''': {{xt|'''Petrarch''' (1304{{ndash}}1374) was{{nbsp}}...}};{{nbsp}} not {{!xt|(1304{{ndash}}74)}}
** Although non-abbreviated years are generally {{em|preferred}}, '''two-digit ending years''' ({{xt|1881{{ndash}}82}}, but never {{!xt|1881{{ndash}}882}} or {{!xt|1881{{ndash}}2}}) {{em|may}} be used in any of the following cases: (1) two consecutive years; (2) ] and tables where space is limited (using a single format consistently in any given table column); and (3) in certain topic areas if there is a very good reason, such as matching the established convention of reliable sources.{{efn|A change from a preference for two digits, to a preference for four digits, on the right side of ''year{{ndash}}year'' ranges was implemented in July 2016 per ].<!--The change can be seen at https://en.wikipedia.org/?diff=744053720&oldid=744052603-->}} For consistency, avoid abbreviated year ranges when they would be used alongside non-abbreviated ranges within an article (or related pages, if in titles). Never use abbreviated years for ranges across centuries ({{xt|1999{{ndash}}2000}}, not {{!xt|1999{{ndash}}00}}) or for years from the first millennium ({{xt|886{{ndash}}887}}, not {{!xt|886{{ndash}}87}}).
:* '''different centuries''': {{xt|1881{{ndash}}1903}};{{nbsp}} not {{!xt|1881{{ndash}}03}}
** The '''{{visible anchor|slash notation}}''' ({{xt|2005/2006}}) may be used to signify a fiscal year or other special period, if that convention is used in reliable sources.
:* '''starting year before 1000{{nbsp}}AD''': {{xt|355{{ndash}}372}} (not {{!xt|355{{ndash}}72}});{{nbsp}} {{xt|95{{ndash}}113}};{{nbsp}} {{xt|95{{ndash}}113{{nbsp}}AD}};{{nbsp}} {{xt|AD{{nbsp}}95{{ndash}}113}};{{nbsp}} {{xt|982{{ndash}}1066}};{{nbsp}} {{xt|2590{{ndash}}2550{{nbsp}}BCE}};{{nbsp}} {{xt|1011{{ndash}}922{{nbsp}}BC}}
* Other "simple" ranges use an {{em|unspaced}} en dash as well:
:: ''Markup: ''<code>1011{{t|ndash}}922{{t|nbsp}}BC</code>
:* '''spanning from BC/BCE to AD/CE''': {{xt|42{{nbsp}}BC{{snd}}15{{nbsp}}AD}} (note ''spaced'' en dash) ** '''day{{ndash}}day''': {{xt|5{{ndash}}7{{nbsp}}January 1979}};{{nbsp}} {{xt|January{{nbsp}}5{{ndash}}7, 1979}};{{nbsp}} {{xt|elections were held March 5{{ndash}}8}}.
** '''month{{ndash}}month''': {{xt|the 1940 peak period was May{{ndash}}July}};{{nbsp}} {{xt|the peak period was May{{ndash}}July{{nbsp}}1940}};{{nbsp}} (but {{xt|the peak period was {{nobr|May 1940{{snd}}July}} 1940}} uses a {{em|spaced}} en dash; {{crossref|see below}})
::{{hanging indent|text=''Markup:'' <code>42{{t|nbsp}}BC{{t|snd}}15{{t|nbsp}}AD</code> ''or'' {{nowrap|<code>42&amp;nbsp;BC&amp;nbsp;&amp;ndash; 15&amp;nbsp;AD</code>}} }}
* In certain cases where at least one item on either side of the en dash contains a space, then a {{em|spaced}} en dash ({{tlx|snd}}) is used. For example:
: ''Notes:''
** '''between specific dates in different months''': {{xt|They travelled {{nobr|June 3{{snd}}August{{nbsp}}18,}} 1952}};{{nbsp}} {{xt|They travelled 3 June{{snd}}18{{nbsp}}August 1952}}
:* Periods straddling two different years, including sports seasons, are generally written with the range notation ({{xt|2005{{ndash}}06}}). The slash notation ({{xt|2005/06}}) may be used to signify a fiscal year or other special period, if that convention is used in reliable sources.
** '''between dates in different years''':
:* A date range may appear in {{xt|2005{{ndash}}2010}} format if it is a range of sports seasons in an infobox.<ref>{{section link|Misplaced Pages talk:Manual of Style/Dates and numbers/Archive 144|Date range redux}}</ref> This format is also indicated for date ranges appearing in reference citations if any dates (of publication, access, archival) are in {{var|YYYY-MM-DD}} format, because the range in question could thus be easily mistaken for a {{var|yyyy-mm}} date: {{xt|''XYZ Annual Review'', 2005{{ndash}}2006. Accessed 2013-04-07.}} but not {{!xt|''XYZ Annual Review'', 2005{{ndash}}06. Accessed 2013-04-07.}} Another case is in tables (and lists the items of which begin with date ranges) in which some but not all date ranges span a century (sortability of a date column in a table also requires a consistent format for all entries: <code>2005{{ndash}}07</code> will unintentionally sort before <code>2005{{ndash}}2006</code>).
*** {{xt|'''Charles Robert Darwin''' (12{{nbsp}}February {{nobr|1809{{snd}}19 April}} 1882) was an English naturalist{{nbsp}}...}}
* Other "pure" ranges use an ''unspaced'' en dash as well:
**** ''Markup:'' <code>12{{t|nbsp}}February 1809{{tl|snd}}19{{t|nbsp}}April 1882</code> or {{nowrap|<code>12&amp;nbsp;February 1809&amp;nbsp;&amp;ndash; 19&amp;nbsp;April 1882</code>}}
:* '''day{{ndash}}day''': {{xt|5{{ndash}}7{{nbsp}}January 1979}};{{nbsp}} {{xt|January{{nbsp}}5{{ndash}}7, 1979}};{{nbsp}} {{xt|elections were held March 5{{ndash}}8}}
*** {{xt|'''Abraham Lincoln''' (February{{nbsp}}12, 1809{{snd}}April{{nbsp}}15, 1865) was the 16th president of{{nbsp}}...}}
:* '''month{{ndash}}month''': {{xt|the 1940 peak period was May{{ndash}}July}};{{nbsp}} {{xt|the peak period was May{{ndash}}July 1940}};{{nbsp}} (but {{xt|the peak period was May {{nobr|1940{{snd}}July}} 1940}} uses a ''spaced'' en dash{{mdashb}}see below)
** '''between months in different years''': {{xt|The exception was in force August {{nobr|1892{{snd}}January}} 1903}};{{nbsp}} {{xt|The Ghent Incursion (March 1822{{snd}}January{{nbsp}}1, 1823) was ended by the New Year's Treaty}}
* If at least one of the items on either side of the en dash is in a "mixed" format (containing two or more of day, month, year); carries a modifier such as {{circa}}; or otherwise contains a space; then a ''spaced'' en dash ({{tlx|snd}}) is used:
*** ''Markup:'' <code>March 1822{{t|snd}}January{{t|nbsp}}1, 1823</code> or {{nowrap|<code>March 1822&amp;nbsp;&amp;ndash; January&amp;nbsp;1, 1823</code>}}
:* '''between specific dates in different months''': {{xt|They travelled {{nobr|June{{nbsp}}3{{snd}}August{{nbsp}}18,}} 1952}};{{nbsp}} {{xt|They travelled 3{{nbsp}}June{{snd}}18{{nbsp}}August 1952}}
** Where '''era designations''', '''c.<!-- guideline below advocates against use of the unabbreviated "circa" or use of italics for "c." -->''' or '''other modifiers''' are present {{See below|{{section link||Uncertain, incomplete, or approximate dates}}}}:
:* '''between dates in different years''':
*** if the modifier '''applies to only one of the two endpoints of the range''', use a {{em|spaced}} en dash: {{nobr|{{xt|150 BCE{{snd}}50 BCE}}}}, {{nobr|{{xt|5 BC{{snd}}12 AD}}}}, {{nobr|{{xt|c. 1393{{snd}}1414}}}}
:: {{xt|'''Charles Robert Darwin''' (12{{nbsp}}February {{nobr|1809{{snd}}19{{nbsp}}April}} 1882) was an English naturalist{{nbsp}}...}}
*** if the modifier '''applies to the range as a whole''', {{em|disregard}} the modifier: {{nobr|{{xt|150{{ndash}}50 BCE}}}}, {{nobr|{{xt|reigned 150 BCE{{snd}}50 BCE}}}}, {{nobr|{{xt|reigned 150{{ndash}}50 BCE}}}}, {{nobr|{{xt|{{reign|{{circa|1393|lk=no}}|1414}}}}}}, {{nobr|{{xt|{{reign|1393|1414|lk=no}}}}}}.
:: {{hanging indent|text=''Markup:'' <code>12{{t|nbsp}}February 1809{{t|snd}}19{{t|nbsp}}April 1882</code> ''or'' {{nowrap|<code>12&amp;nbsp;February 1809&amp;nbsp;&amp;ndash; 19&amp;nbsp;April 1882</code>}} }}
* Use an en dash, or a word such as ''from'' or ''between'', but not both: {{xt|from 1881 to 1886}} (not {{!xt|{{nobr|from 1881{{ndash}}1886}}}});{{nbsp}} {{xt|between June{{nbsp}}1 and July{{nbsp}}3}} (not {{!xt|{{nobr|between June{{nbsp}}1{{snd}}July{{nbsp}}3}}}})
:: {{xt|'''Abraham Lincoln''' (February{{nbsp}}12, 1809{{snd}}April{{nbsp}}15, 1865) was the 16th President of{{nbsp}}...}}
{{shortcut|MOS:DATETOPRES|MOS:TOPRESENT}}{{anchors|Date range to present}}
:* '''between months in different years''': {{xt|The exception was in force August {{nobr|1892{{snd}}January}} 1903}};{{nbsp}} {{xt|The Ghent Incursion (March 1822{{snd}}January{{nbsp}}1, 1823) was ended by the New Year's Treaty}}
* ] says "terms such as ... 'present' should usually be avoided". For ranges, if '''"to present"''' or '''"{{ndash}}present"''' is used, the current year (or, in cases where necessary, date) of "present" at the time of writing should be included. Thus {{nobr|{{xt|1982{{ndash}}present (as of {{CURRENTYEAR}})}}}}{{snd}}if writing in {{CURRENTYEAR}}{{snd}}is preferable to {{nobr|{{xt|1982{{ndash}}present}}}}. If the "from" date has an internal space, a spaced en dash is used. Other constructions may be more appropriate in prose {{crossref|(see {{section link||Statements likely to become outdated}})}}. An alternative form is {{xt|Since 1982}}.
::{{hanging indent|text=''Markup:'' <code>March 1822{{t|snd}}January{{t|nbsp}}1, 1823</code> ''or'' {{nowrap|<code>March 1822&amp;nbsp;&amp;ndash; January&amp;nbsp;1, 1823</code>}} }}
* For a person still living: {{xt|'''Serena Williams''' (born September{{nbsp}}26, 1981) is a{{nbsp}}...}}, not {{!xt|(September{{nbsp}}26, 1981{{ndash}})}} or {{!xt|(born on September{{nbsp}}26, 1981)}}
* An overnight period may be expressed using a slash between two contiguous dates: {{xt|the night raids of 30/31{{nbsp}}May 1942}} or {{xt|raids of 31{{nbsp}}May{{nbsp}}/ 1{{nbsp}}June 1942}}.
: Or use an en dash: (unspaced) {{xt|raids of 30{{ndash}}31{{nbsp}}May 1942}};{{nbsp}} (spaced) {{xt|raids of {{nobr|31{{nbsp}}May{{snd}}1{{nbsp}}June}} 1942}}.
* Use a dash, or a word such as ''from'' or ''between'', but not both: {{xt|from 1881 to 1886}} (not {{!xt|{{nobr|from 1881{{ndash}}86}}}});{{nbsp}} {{xt|between June{{nbsp}}1 and July{{nbsp}}3}} (not {{!xt|{{nobr|between June{{nbsp}}1{{snd}}July{{nbsp}}3}}}})


:In tables and infoboxes where space is limited, ''pres.'' may be used ({{xt|1982{{ndash}}pres.}}). Do not use incomplete-looking constructions such as {{nobr|{{!xt|1982{{ndash}}}}}} and {{nobr|{{!xt|1982{{ndash}}... }} .}}
Use ] for age calculations in infoboxes and so on; see ].
:*Consider adding the {{t|As of}}, or {{t|Update after}} templates to such constructions, depending on how important it is for editors to keep "present" up to date.

* <p>For a '''person still living''': {{xt|'''Serena Williams''' (born September{{nbsp}}26, 1981) is a{{nbsp}}...}}, not {{!xt|(September{{nbsp}}26, 1981{{snd}})}} or {{!xt|(born on September{{nbsp}}26, 1981)}}.</p><p>Do not use <code>*</code> to indicate ''born''; use <code>b.</code> only where space is limited, e.g., in tables and infoboxes; use either <code>born</code> or <code>b.</code> consistently in any given table column.</p>
* <p>Where '''birthdate is unknown''': {{xt|'''John Smith''' (died May{{nbsp}}1, 1622)}} or {{xt|'''John Smith''' (died 1622)}}</p><p>Do not use <code>†</code> to indicate ''died''; use <code>d.</code> only where space is limited, with consistency within any given table column.</p>
* <p>An '''overnight period''' may be expressed using a slash between two contiguous dates: {{xt|the night raids of 30/31{{nbsp}}May 1942}} or {{xt|raids of 31{{nbsp}}May{{nbsp}}/ 1{{nbsp}}June 1942}}.</p><p>Or use an en dash: (unspaced) {{xt|raids of 30{{ndash}}31{{nbsp}}May 1942}};{{nbsp}} (spaced) {{xt|raids of {{nobr|31{{nbsp}}May{{snd}}1{{nbsp}}June}} 1942}}.</p>
* The {{tlx|Age}} template can keep ages current in infoboxes and so on:
** <code><nowiki>{{age|1989|7|23}}</nowiki></code> returns: {{xt|{{age|1989|7|23}}}}
** <code><nowiki>{{age|1989|7|23}}-year-old</nowiki></code> returns: {{xt|{{age|1989|7|23}}-year-old}}
** <code><nowiki>{{age|1989|7|23}} years old</nowiki></code> returns: {{xt|{{age|1989|7|23}} years old}}
* ] are available for other age calculations.


====Uncertain, incomplete, or approximate dates==== ====Uncertain, incomplete, or approximate dates====

* To indicate ''around,'' ''approximately'', or ''about'', the use of the spaced, unitalicised form {{xt|c.{{nbsp}}1291}} (or the {{tlx|circa}} template) is preferred over {{!xt|circa}}, {{!xt|ca}}, {{!xt|ca.}}, {{!xt|approximately}}, or {{!xt|approx.}}:
<!--This section/anchor linked to from MOS:DATERANGE.-->
:&nbsp; &bull; &nbsp; {{xt|At the birth of Roger Bacon (c. 1214){{nbsp}}...}}
{{shortcut|MOS:APPROXDATE|MOS:CIRCA}}
:&nbsp; &bull; &nbsp; {{xt|'''John Sayer''' ({{circa}} 1750{{snd}}2{{nbsp}}October 1818){{nbsp}}...}}
* To indicate "around", "approximately", or "about", the use of the {{tlx|circa}} template is preferred at first occurrence over just {{!xt|c.}} At later occurrences, {{xt|c.}} is preferred over {{!xt|circa}}, {{!xt|c}}, {{!xt|ca}}, {{!xt|ca.}}, {{!xt|around}}, {{!xt|approximately}}, or {{!xt|approx.}}:
:&nbsp; &bull; &nbsp; {{xt|the Igehalkid dynasty of Elam, {{circa}} 1400{{nbsp}}BC{{nbsp}}...}}
** {{xt|'''John Sayer''' ({{circa|1750}}{{snd}}2{{nbsp}}October 1818){{nbsp}}...}}
* Where both endpoints of a range are approximate, c. should appear before each date:
** {{xt|the Igehalkid dynasty of Elam, {{circa|1400{{nbsp}}BC}}{{nbsp}}...}}
:&nbsp; &bull; &nbsp; {{xt|'''Dionysius Exiguus''' ({{circa}} 470{{snd}}{{circa}} 540){{nbsp}}...}} (not {{!xt|'''Dionysius Exiguus''' ({{circa}} 470{{snd}}540){{nbsp}}...}})
* Where both endpoints of a range are approximate, <code>c.</code> should appear before each date (the two-argument form of {{tlx|circa}} does this):
:&nbsp; &bull; &nbsp; {{xt|'''Rameses III''' (reigned {{circa}} 1180{{snd}}{{circa}} 1150{{nbsp}}BCE){{nbsp}}...}} (not {{!xt|'''Rameses III''' (reigned {{circa}} 1180{{snd}}1150{{nbsp}}BCE){{nbsp}}...}})
** {{xt|'''Dionysius Exiguus''' ({{circa|470|540}}){{nbsp}}...}} (not {{!xt|'''Dionysius Exiguus''' ({{circa}} 470{{snd}}540){{nbsp}}...}})
* Where birth/death dates have been extrapolated from known dates of activity:
:&nbsp; &bull; &nbsp; {{xt|'''Offa of Mercia''' (before 734{{snd}}26{{nbsp}}July 796){{nbsp}}...}} ** {{xt|'''Rameses III''' (reigned {{circa|1180|1150{{nbsp}}BCE}}){{nbsp}}...}} (not {{!xt|'''Rameses III''' (reigned {{circa}} 1180{{snd}}1150{{nbsp}}BCE){{nbsp}}...}})
* Where birth/death limits have been inferred from known dates of activity:
:&nbsp; &bull; &nbsp; {{xt|'''Robert Menli Lyon''' (1789{{snd}}after 1863){{nbsp}}...}}
:&nbsp; &bull; &nbsp; {{xt|'''Ambrose Gwinnett Bierce''' (June 24, 1842{{snd}}after December 26, 1913){{nbsp}}...}} <!-- relationship between "before/after" and "fl" needs to be clarified--> ** {{xt|'''Offa of Mercia''' (before 734{{snd}}26{{nbsp}}July 796){{nbsp}}...}}
** {{xt|'''Robert Menli Lyon''' (1789{{snd}}after 1863){{nbsp}}...}}
* When a person is known to have been active ("flourishing") during certain years, {{xt|fl.}}, <code><nowiki>]</nowiki></code>, or {{tlx|fl.}} may be used:
** {{xt|'''Ambrose Gwinnett Bierce''' (June 24, 1842{{snd}}after December 26, 1913){{nbsp}}...}}<!--Relationship between "before/after" and "fl." needs to be clarified.-->
:&nbsp; &bull; &nbsp; {{xt|'''Osmund''' ({{fl.|760{{ndash}}772}}){{nbsp}}...}}
* When birth and death dates are unknown, but the person is known to have been active ("flourishing") during certain years, {{xt|fl.}}, <code><nowiki>]</nowiki></code>, or {{tlx|fl.}} may be used:
: The linked forms should not be used on disambiguation pages, and "active" followed by the range is a better alternative for artists, soldiers and other persons with an occupation.<!-- Huh? As opposed to kings, queens, and clergymen, who sit around all day? What about mathematicians -- do they have an "occupation"? -->
** {{xt|'''Jacobus Flori''' (]{{nbsp}}1571{{ndash}}1588) ...}}
** {{xt|'''Jacobus Flori ''fils''''' ({{floruit|{{circa|1600}}{{snd}}1616|lk=off}}) ...}}<!-- example used to illustrate that not all uses of "fl." will require an unspaced en dash -->
: The corresponding template {{tlx|r.}} produces reign output: {{xt|{{r.|540|562}}}}, though it is often clearer to write out {{xt|reigned 540–562}}, especially in the lead. With both of these templates, linked forms should not be used on disambiguation pages, and "active" followed by the range is a better alternative for occupations not relating to the composition of works, whether it be musical, grammatical, historical, or any other such work.
* When a date is known to be either of two years (e.g. from a ] or ] year conversion, or a known age at death): * When a date is known to be either of two years (e.g. from a ] or ] year conversion, or a known age at death):
: &nbsp; &bull; &nbsp; {{xt|'''Anne Smith''' (born 1912 or 1913; died 2013){{nbsp}}...}} ** {{xt|'''Anne Smith''' (born 1912 or 1913; died 2013){{nbsp}}...}}
* Other forms of uncertainty should be expressed in words, either in article text or in a footnote: {{xt|April{{nbsp}}14, 1224 (unattested date)}}. Do not use a question mark ({{!xt|1291?}}) for such purposes, as this fails to communicate the nature of the uncertainty. * Other forms of uncertainty should be expressed in words, either in article text or in a footnote: {{xt|April{{nbsp}}14, 1224 (unattested date)}}. Do not use a question mark ({{!xt|1291?}}), because it fails to communicate the nature of the uncertainty.
* Where {{xt|c.}} or a similar form appears ''which applies only to one of the two endpoints of the range'', use a spaced en dash (<code><nowiki>{{snd}}</nowiki></code>).
** ''Examples'': {{xt|{{nobr|1896{{snd}}after 1954}}}}, {{xt|{{nobr|470{{snd}}{{c.|540}}}}}}, {{xt|{{nobr|{{c.|470}}{{snd}}540}}}}, {{xt|{{nobr|{{c.|470|540}}}}}}.
** ''Markup'': {{nobr|<code><nowiki>1896{{snd}}after 1954</nowiki></code>}}, {{nobr|<code><nowiki>470{{snd}}{{c.|540}}</nowiki></code>}}, {{nobr|<code><nowiki>{{c.|470}}{{snd}}540</nowiki></code>}}, {{nobr|<code><nowiki>{{c.|470|540}}</nowiki></code>}}.<!-- n.b.: the {{c}} template is unrelated, as it deals with linking to categories -->
* Where a modifier ''applies to the range as a whole'', such as {{xt|fl.}} and {{xt|{{abbr|r.|reigned}}}}, use a spaced or unspaced en dash as appropriate to the range if this modifier is disregarded.
** ''Examples'': {{xt|]{{nbsp}}1571{{ndash}}1588}}, {{xt|{{floruit|{{circa|1600}}{{snd}}1616|lk=off}}}}, {{xt|{{reign|{{circa|1353}}|1336}}{{nbsp}}BC}}, {{xt|{{reign|1989|2019|lk=no}}{{nbsp}}CE}}, {{xt|{{reign|2019{{nbsp}}CE|present|lk=no}}}}.
* Some modifiers, such as {{xt|traditionally}}, {{xt|around}}, {{xt|BH}}, and {{xt|CE}}, sometimes apply to only one endpoint, and sometimes to the whole range. Whether the en dash should be spaced or unspaced should still be determined by the above guidelines, but consider rephrasing if the result is ambiguous or possibly confusing.
** {{nobr|{{xt|traditionally 1571{{ndash}}1588}}}} and {{nobr|{{xt|traditionally 1571{{snd}}1588}}}} mean two different things, which may not be obvious to the reader.
** {{nobr|{{xt|traditionally 1585{{snd}}{{circa|1590}}}}}} can have two different meanings, and which one is meant may not be clear.
** {{nobr|{{!xt|400 BCE{{snd}}200}}}} clearly has {{xt|BCE}} applying only to one endpoint, but the range is ambiguous. Consider using {{nobr|{{xt|400{{ndash}}200 BCE}}}}, {{nobr|{{xt|400 BCE{{snd}}200 BCE}}}}, or {{nobr|{{xt|400 BCE{{snd}}200 CE}}}}, depending on what is meant.
** Technically, {{nobr|{{!xt|] 13{{snd}}57}}}} is currently<!-- it may not be in the future --> unambiguous (because there is no Taishō 57), but it is better to use both era designations in this case: {{nobr|{{xt|] 13{{snd}}] 57}}}}.
* Ideally a non-breaking space should follow very short modifiers such as {{xt|c.}}, {{xt|fl.}}, {{xt|r.}}, {{xt|{{abbr|b.|born}}}}, and {{xt|{{abbr|d.|died}}}}

===Times of day<span id="Time of day"></span>===

{{Shortcut|MOS:TIME|MOS:AMPM}}

Context determines whether the ] or ] clock is used. In all cases, colons separate hours, minutes, and (where present) seconds, e.g. {{xt|1:38:09{{nbsp}}pm}} or {{xt|13:38:09}}. Use figures ({{xt|11{{nbsp}}a.m.}} or {{xt|12:45{{nbsp}}p.m.}}) rather than words ({{!xt|twelve forty-five p.m.}}).
* '''12-hour clock times''' end with lower-case {{xtn|a.m.}} or {{xtn|p.m.}}, or {{xtn|am}} or {{xtn|pm}}, preceded by a ], e.g. {{xt|2:30{{nbsp}}p.m.}} or {{xt|2:30{{nbsp}}pm}} (markup: <code>2:30{{tl|nbsp}}p.m.</code> or <code>2:30{{tl|nbsp}}pm</code>), not {{!xt|2:30p.m.}} or {{!xt|2:30pm}}. Hours should not have a leading zero (e.g. {{xt|2:30{{nbsp}}p.m.}}, not {{!xt|02:30{{nbsp}}p.m.}}). Usually, use {{xt|noon}} and {{xt|midnight}} rather than {{!xt|12 pm}} and {{!xt|12 am}}; whether "midnight" refers to the start or the end of a date should be explicitly specified unless clear from the context. Where several times that are all a.m. or all p.m. appear in close proximity, then ''a.m.'' or ''p.m.'' need be given only once if there is no risk of confusion.
* '''24-hour clock times''' have no a.m., p.m., noon or midnight suffix, and include a colon ({{xt|15:30}} not {{!xt|1530}}). Hours under 10 should have a leading zero ({{xt|08:15}}). The time {{xt|00:00}} refers to midnight at the start of a date, {{xt|12:00}} to noon, and {{xt|24:00}} to midnight at the end of a date, but {{!xt|24}} should not be used for the first hour of the next day (e.g. use {{xt|00:10}} for ten minutes after midnight, not {{!xt|24:10}}).

====Time zones====

{{shortcut|MOS:TIMEZONE}}
Give dates and times appropriate to the ] where an event took place. For example, the date of the ] should be December{{nbsp}}7, 1941 (Hawaii time/{{zwsp}}date). Give priority to the place at which the event had its most significant effects; for example, if a hacker in Monaco attacked a Pentagon computer in the US, use the time zone for the Pentagon, where the attack had its effect. In some cases, the best solution may be to add the date and time in ] (UTC). For example:

{{in5}}{{xt|8{{nbsp}}p.m. ] on January{{nbsp}}15, 2001 (01:00{{nbsp}}UTC, January{{nbsp}}16)}}

Alternatively, include just the ]:

{{in5}}{{xt|21:00{{nbsp}}] (]) on 27{{nbsp}}July 2012}}

Rarely, the time zone in which an event took place has since changed; for example, China until 1949 was divided into ], whereas all of modern China is one time zone; ]. Similarly, the term "UTC" is not appropriate for dates before this system was adopted in 1960;<ref>{{cite book |id=CCTF/09-32 |title=Coordinated Universal Time (UTC) |date=June 2, 2009 |publisher=] |page=3 |quote=This coordination began on January 1, 1960, and the resulting time scale began to be called informally 'Coordinated Universal Time.'&thinsp; |url= https://www.bipm.org/documents/20126/28435864/working-document-ID-3644/2a6ce17c-7b50-4164-9bee-64f77bfad895 |format=PDF |access-date=October 5, 2022}}</ref> ] (UT) is the appropriate term for the mean time at the ] when it is unnecessary to specify the precise definition of the time scale. Be sure to show the UTC or offset appropriate to the clock time in use at the time of the event, not the modern time zone, if they differ.

<span id="Day, month and season names"></span><span id="Longer periods"></span><span id="Other periods"></span><span id="Other"></span>
===Days of the week===
* Where space is limited (e.g. tables), days of the week may be abbreviated as {{xt|Sun}}, {{xt|Mon}}, {{xt|Tue}}, {{xt|Wed}}, {{xt|Thu}}, {{xt|Fri}}, {{xt|Sat}} (without dots, i.e. not {{!xt|Sun'''.'''<!--bolding to make dots more obvious-->}}, {{!xt|Mon'''.'''}}, etc.).

===Seasons of the year<span id="Seasons"></span>===


<!--Misplaced Pages:Manual of Style/Words to watch#Relative time references links to this section.-->{{shortcut|MOS:SEASON}}
===<span id="Day, month and season names" /><span id="Longer periods" /><span id="Other periods"/>Other===
* Avoid using seasons to refer to a particular time of year, as they are often unduly ambiguous: {{!xt|Spring 1995}} began in the Southern Hemisphere six months after it did in the Northern Hemisphere; winter spans two calendar years in the Northern Hemisphere, but not in the Southern Hemisphere. Moreover, areas near the Equator have only ] and ]s. Unambiguous alternatives include {{xt|early{{nbsp}}1995}}; {{xt|the second quarter of 1995}}; {{xt|March to June{{nbsp}}1995}}; {{xt|spent the southern autumn in Antarctica}}.
====Days of the week====
** Referring to a season by name is appropriate when it is part of a conventional name or designation ({{xt|annual mid-winter festival}}; {{xt|the autumn harvest}}; {{xt|the court's winter term}}; {{xt|the magazine's summer 2015 issue}}).
*Days of the week are capitalized ({{xt|Sunday}}, {{xt|Wednesday}}).
* Season names are generally not capitalized ({{xt|a hot summer}}), except when personified ({{xt|Old Man Winter}}) or when part of a formal name ({{xt|2018{{nbsp}}Winter Olympics}}; {{xt|Arab Spring}}) that is capitalized under the ]. They are capitalized when part of the title of a work ({{xt|''Science Fiction Quarterly'', Summer 1942}}), except that seasonal editions may be lower-cased in running text ({{xt|the Summer 1985 issue of ''Interzone''}} or {{xt|the summer 1985 issue of ''Interzone''}}).


====Seasons==== ===Decades===
{{shortcut|WP:SEASON|MOS:SEASON}}
* Seasons are uncapitalized ({{xt|a hot summer}}) except when personified: {{xt|Soon Spring will show her colors}}; {{xt|Old Man Winter}}.
* Using seasons to refer to a particular time of year ({{!xt|winter 1995}}) is ambiguous, because Northern and Southern Hemisphere seasons are six months out of phase, and many areas near the equator instead have ] and ]s. Consider alternative phrasing: {{xt|early 1995}};{{nbsp}} {{xt|the first quarter of 1995}};{{nbsp}} {{xt|January to March 1995}}; {{nbsp}} {{xt|spent the southern summer in Antarctica}}.
* However, using seasons is appropriate when referring to seasonal events: {{xt|the autumn harvest}};{{nbsp}} {{xt|migration typically begins in mid-spring}}.


{{shortcut|MOS:DECADE|MOS:DECADES}}
====Decades====
* To refer to a decade as a chronological period {{lang|la|per se}} (not with reference to a social era or cultural phenomenon), always use four digits and an ''s'', as in {{xt|the{{nbsp}}1980s}}. Do not use {{!xt|the{{nbsp}}1980's}}, or {{!xt|the{{nbsp}}1980{{nbh}}ies}}.
{{shortcut|WP:DECADE|MOS:DECADE}}
** Prefixes should be hyphenated ({{xt|the{{nbsp}}mid{{nbh}}1980s}};{{nbsp}} {{xt|pre{{nbh}}1960s social attitudes}}).<!--Non-breaking hyphens {{nbh}} are used in some examples to keep them from being fragmented over linebreaks here in MOS; that's not to say {{nbh}} ought to be used in "real life" in such situations.-->
* To refer to a decade as a chronological period ''per se'' (not with reference to a social era or cultural phenomenon) always use four digits ({{xt|the{{nbsp}}1980s}}, but not {{!xt|the{{nbsp}}1980's}} or {{!xt|the{{nbsp}}1980{{nbh}}ies}}, and ''definitely'' not {{!xt|the{{nbsp}}1980s'}}).
** Adjectives should not be hyphenated ({{xt|the late 1950s, the early 1970s}}).
:* Prefixes should be hyphenated ({{xt|the{{nbsp}}mid{{nbh}}1980s}};{{nbsp}} {{xt|pre{{nbh}}1960s social attitudes}}).<!-- nonbreaking hyphens {{nbh}} are used in some examples to keep them from being fragmented over linebreaks here in MOS -- that's not to say nbh ought to be used in "real life" in such situations -->
* For a social era or cultural phenomenon associated with a particular decade: * For a social era or cultural phenomenon associated with a particular decade:
:* Two digits (with a preceding apostrophe) may be used as an alternative to four digits, ''but only if this is a well-established phrase seen in reliable sources'' ({{xt|the{{nbsp}}Roaring{{nbsp}}'20s}},{{nbsp}} {{xt|the{{nbsp}}Gay{{nbsp}}'90s}},{{nbsp}} {{xt|condemning the '60s counterculture}}, but {{xt|grew up in 1960s Boston, moving to Dallas in{{nbsp}}1971}}, and do not write {{!xt|the{{nbsp}}90's}};{{nbsp}} {{!xt|the{{nbsp}}90s}};{{nbsp}} or {{!xt|the{{nbsp}}90s'}}). ** Two digits (with a preceding apostrophe) may be used as an alternative to four digits, but only in well-established phrases seen in reliable sources: {{xt|the{{nbsp}}Roaring{{nbsp}}'20s}}; {{xt|the{{nbsp}}Gay{{nbsp}}'90s}}; {{xt|condemning the '60s counterculture}}{{mdash}}but {{xt|grew up in 1960s Boston, moving to Dallas in{{nbsp}}1971}}. Do not write: {{!xt|the{{nbsp}}90's}}; {{!xt|the{{nbsp}}90s}}; or {{!xt|the{{nbsp}}90s'}}.
:* A third alternative (where seen in reliable sources) is to spell the decade out, capitalized: {{xt|changing attitudes of the Sixties}} ** Another alternative (where seen in reliable sources) is to spell the decade out, capitalized: {{xt|changing attitudes of the Sixties}}.


====<span id="centuries" /><span id="millennia" />Centuries and millennia==== ===Centuries and millennia<span id="centuries"></span><span id="millennia"></span>===
{{shortcut|WP:CENTURY|WP:MILLENNIUM}}
* Treat the 1st century AD as years {{nobr|1{{ndash}}100}}, the 17th century as {{nobr|1601{{ndash}}1700}}, and the second millennium as {{nobr|1001{{ndash}}2000}}; similarly, the 1st century BC/BCE was {{nobr|100{{ndash}}1}} BC/BCE, the 17th century was {{nobr|1700{{ndash}}1601}} BC/BCE, and the second millennium {{nobr|2000{{ndash}}1001}} BC/BCE.
** The ''18th century'' ({{nobr|1701{{ndash}}1800}}) and the ''1700s'' ({{nobr|1700{{ndash}}1799}}) are not the same period.
** When using forms such as {{xt|the 1700s}} ensure there is no ambiguity as to whether e.g. {{nobr|1700{{ndash}}1709}} or {{nobr|1700{{ndash}}1799}}, is meant.<!-- this needs a little ironing out re "1700s"-->
** Note that the sequence of years runs ''...{{nbsp}}2{{nbsp}}BC, 1{{nbsp}}BC, 1{{nbsp}}AD, 2{{nbsp}}AD{{nbsp}}...''{{mdashb}}there is no "]".
* Centuries and millennia are identified using either figures ({{xt|the 18th{{nbsp}}century}}, not {{!xt|XVIII century}}) or words ({{xt|the second millennium}}).<!--actually, I wonder whether "1st millennium" and "2nd millennium" are really appropriate -- they look funny--> When used adjectivally they contain a hyphen ({{xt|nineteenth-century painting}} or {{xt|19th-century painting}}). Do not capitalize ({{!xt|the best Nineteenth-century paintings}};{{nbsp}} {{!xt|during the Nineteenth Century}}).
:* See ] for use of hyphens and dashes in obscure situations.


{{shortcut|MOS:CENTURY|MOS:MILLENNIUM}}
====<span id="Abbreviations for long periods of time"/>Long periods of time====

* When the term is frequent, combine "yr" for "years" or "ya" for "years ago" with "k" for "thousand" (kya, kyr), "m" for "million" (mya, ]), or "b" for "billion" (], byr).
The sequence of numbered years in dates runs {{xt|...{{nbsp}}2{{nbsp}}BC, 1{{nbsp}}BC, 1{{nbsp}}AD, 2{{nbsp}}AD{{nbsp}}...}}; there is no "]".
* In academic contexts, ]-based units are often used: "ka" (kiloannum), "Ma" (megaannum) and "Ga" (gigaannum).
* Treat the 1st century AD as years {{nobr|1{{ndash}}100}}, the 17th century as {{nobr|1601{{ndash}}1700}}, and the second millennium as {{nobr|1001{{ndash}}2000}}; similarly, the 1st century BC{{\}}BCE was {{nobr|100{{ndash}}1}} BC{{\}}BCE, the 17th century BC{{\}}BCE was {{nobr|1700{{ndash}}1601}} BC{{\}}BCE, and the second millennium {{nobr|2000{{ndash}}1001}} BC{{\}}BCE.
* Show the meaning parenthetically on first occurrence and again where use is extensive,{{huh}} or might be a standalone topic of interest.{{huh}} In source quotations use square brackets: {{xt|"a measured Libby radiocarbon date of 35.1{{nbsp}}mya required calibration ..."}}
* Centuries and millennia are identified using either Arabic numerals ({{nobr|{{xt|the 18th century}}}}) or words ({{xt|the second millennium}}), with in-article consistency (] notwithstanding). When used adjectivally they contain a hyphen ({{xt|nineteenth-century painting}} or {{xt|{{nobr|19th-century}} painting}}). Do not use superscripts ({{!xt|19<sup>th</sup> century}}).
* Do not capitalize ({{!xt|the best Nineteenth-century paintings}};{{nbsp}}{{!xt|during the Nineteenth Century}}).
* Do not use ] ({{!xt|XVIII{{nbsp}}century}}).
* {{xt|The 18th century}} refers to the period ({{nobr|1701{{ndash}}1800}}), while strictly {{!xt|the 1700s}} refers either to ({{nobr|1700{{ndash}}1799}}) or ({{nobr|1700{{ndash}}1709}})
** When using forms such as {{xt|the 1900s}}, ensure there is no ambiguity as to whether the century or the decade is meant.
* {{crossref|See {{section link|WP:Manual of Style|En dashes}} for use of hyphens and dashes in obscure situations.}}

===Long periods of time<span id="Abbreviations for long periods of time"></span>===

* When the term is frequent, combine {{xtn|yr}}{{nbsp}}(years) or {{xtn|ya}}{{nbsp}}(years ago) with {{xtn|k}}{{nbsp}}(thousand): {{xtn|kya}}, {{xtn|kyr}}; {{xtn|M}}{{nbsp}}(million): {{xtn|Mya}}, {{xtn|Myr}}; and {{xtn|b}}{{nbsp}}(] billion): {{xtn|bya}}, {{xtn|byr}}. {{Crossref|(See {{section link|Year|Abbreviations yr and ya}} for more information.)}}
* In academic contexts, ]-based units are often used with an ]: {{xtn|ka}}{{nbsp}}(kiloannus), {{xtn|Ma}}{{nbsp}}(megaannus), and {{xtn|Ga}}{{nbsp}}(gigaannus). {{Crossref|(See {{section link|Year|SI prefix multipliers}} for more information.)}}
* Show the meaning parenthetically, and consider linking to the appropriate section of the ] article {{crossref|({{section link|Year|Abbreviations yr and ya}} or {{section link|Year|SI prefix multipliers}})}} on first occurrence and where the use is a standalone topic of interest. In source quotations, use square brackets: {{xt|"a potassium-argon date of 35.1{{nbsp}}Mya {{nbsp}}..."}}


==Numbers== ==Numbers==
{{redirect-distinguish|MOS:FIGURE|MOS:IMAGE}}

===Numbers as figures or words=== ===Numbers as figures or words===
{{shortcut|WP:NUMERAL|MOS:NUMERAL|WP:SPELL09|MOS:SPELL09}}
''See also information on specific situations, elsewhere in this guideline.''


{{shortcut|MOS:NUMERAL|MOS:SPELL09|MOS:MILLION|MOS:BILLION|MOS:TRILLION|MOS:LAKH|MOS:CRORE}}
Generally, in article text:
{{crossref|Information on specific situations is scattered elsewhere on this page.}}
* Integers from zero to nine are spelled out in words
* Integers greater than nine ''expressible in one or two words'' may be expressed either in numerals or in words ({{xt|16}} or {{xt|sixteen}}, {{xt|84}} or {{xt|eighty-four}}, {{xt|200}} or {{xt|two hundred}}). In spelling out numbers, "components" from 21 to 99 are hyphenated; larger ones are not ({{xt|fifty-six}}, {{xt|five hundred}}).
* Other numbers are given in numerals ({{xt|3.75}}, {{xt|544}}) or in forms such as {{xt|21{{nbsp}}million}}. ''Markup:'' {{nowrap|<code><nowiki>21{{nbsp}}million</nowiki></code>}}
:* ''billion'' and ''trillion'' are understood to represent their ] values of 10<sup>9</sup>{{nbsp}}(1,000,000,000) and 10<sup>12</sup>{{nbsp}}(1,000,000,000,000), respectively.
:* ''M'' (unspaced) and ''bn'' (unspaced) may be used for ''million'' and ''billion'' after spelling out the first occurrence (e.g. {{xt|She received &pound;70 million and her son &pound;10M}}).<!--this needs to be coordinated with text in units tables re nonuse of M (for 1000) MM etc-->
:* SI prefixes and symbols, such as ''giga-'' ''(G)'' and ''tera-'' (''T''), should be restricted to use in scientific and engineering expressions.
:* Sometimes, the ] used in an article may necessitate the use of a numbering system other than the Western thousands-based system. For example, the ] is convention{{shy}}ally used in ]. In those situations, link the first spelled-out instance of each quantity (e.g. <code><nowiki>]</nowiki></code>, which yields ]). (If no instances are spelled out, provide a note after the first instance directing the reader to the article about the numbering system.) Also, provide a conversion to Western numbers for the first instance of each quantity, and provide conversions for subsequent instances if they do not overwhelm the content of the article. For example, write {{xt|three ] (thirty million)}}. Group digits in Western thousands-based style (e.g., {{xt|30,000,000}}; not {{!xt|3,00,00,000}}): see {{section link||Delimiting (grouping of digits)}} below. (Note that the variety of English does not uniquely determine the method of numbering in an article. Other considerations, such as conventions used in mathematics, science and engineering, may also apply, and the choice and order of formats and conversions is a matter of editorial discretion and consensus.)


'''Generally, in article text:'''
{{anchor|Numeral notes}}{{shortcut|WP:NUMNOTES}}
* Integers from zero to nine are spelled out in words.
Notes and exceptions:
* Integers greater than nine {{em|expressible in one or two words}} may be expressed either in numerals or in words ({{xt|16}} or {{xt|sixteen}}, {{xt|84}} or {{nobr|{{xt|eighty-four}}}}, {{xt|200}} or {{nobr|{{xt|two hundred}}}}). When written as words, integers from 21 to 99 that are not multiples of 10 are hyphenated (including when part of a larger number): {{nobr|{{xt|fifty-six}}}} and {{nobr|{{xt|fifty-six thousand}}}}, but {{xt|five{{nbsp}}hundred}} and {{xt|five{{nbsp}}thousand}}.
* In tables and infoboxes, quantities are expressed in figures ({{xt|'''Years in office:'''{{nbsp}}5}}); but numbers within a table's explanatory text and comments follow the general rule.
* Numbers in mathematical formulae are never spelled out ({{xt|3{{nbsp}}<{{nbsp}}π{{nbsp}}<{{nbsp}}22/7}}, not {{!xt|three < π < 22 sevenths}}).
* Comparable quantities should be all spelled out or all in figures:
: &nbsp; &bull; &nbsp;{{xt|five cats and thirty-two dogs}}, not {{!xt|five cats and 32 dogs}}.
: &nbsp; &bull; &nbsp;{{xt|86{{nbsp}}men and 103{{nbsp}}women}}, not {{!xt|eighty-six men and 103 women}}
: &nbsp; &bull; &nbsp;{{xt|There were 3 deaths and 206 injuries}} (even though ''3'' would normally be given as ''three'') or {{xt|Three died and two hundred six were injured}} (even though ''two hundred six'' would normally be given as ''206''), not {{!xt|There were three deaths and 206 injuries}}
* But adjacent quantities not comparable should usually be in ''different formats:'' {{xt|twelve 90-minute volumes}} or {{xt|12 ninety-minute volumes}}, not {{!xt|12 90-minute volumes}} or {{!xt|twelve ninety-minute volumes}}.
:* Avoid awkward juxtapositions: {{xt|On April 28, 2006, thirty-one more died.}}, not {{!xt|On April 28, 2006, 31 more died.}}
* Ages are typically stated in figures ({{xt|8-year-old child}})<!--what is the origin of this provision? should it just say "personal ages..."?--> except for large, approximate values ({{xt|69-million-year-old fossil}}).
* Sometimes figures and words carry different meanings; for example {{xt|Every locker except one was searched}} implies there is a single exception (we don't know which), while {{xt|Every locker except 1 was searched}} means that Locker 1 (only) was not searched.
* Proper names, technical terms, and the like are never altered: {{xt|'']''}};{{nbsp}} {{xt|'']''}};{{nbsp}} {{xt|5{{nbsp}}Channel Street}};{{nbsp}} {{xt|Channel{{nbsp}}5}};{{nbsp}} {{xt|Chanel No. 5}};{{nbsp}} {{xt|Fourth Estate}};{{nbsp}} {{xt|'']''}};{{nbsp}} {{xt|Second Judicial District}};{{nbsp}} {{xt|First Amendment}};{{nbsp}} {{xt|'']''}};{{nbsp}} {{xt|'']''}}


{{anchor|Numeral notes}}{{shortcut|MOS:NUMNOTES}}
* Avoid beginning a sentence with figures:
'''Notes and exceptions:'''
:&nbsp; &bull; &nbsp; Not {{!xt|There were many attacks. 23 men were killed}}, but {{xt|There were many attacks; 23{{nbsp}}men were killed}} or {{xt|There were many attacks. Twenty-three men were killed}}.
* Avoid beginning a sentence with a figure:
:&nbsp; &bull; &nbsp; Not {{nowrap|{{!xt|1945 and 1950 saw crucial elections}}}} (nor {{nowrap|{{!xt|Nineteen forty-five and 1950 saw crucial elections}}}}{{snd}} because comparable numbers should be both written in words or both in figures) but {{nowrap|{{xt|The elections of 1945 and 1950 were crucial.}}}}<!--Examples still need work, and need something about "nineteen forty-five"-type years-->
** Use: {{nowrap|{{xt|There were many matches''';''' 23 ended in a draw.}}}} Or: {{nowrap|{{xt|There were many matches'''.''' Twenty-three ended in a draw.}}}}
:* Exception: Where a proper name, technical term, etc., itself beginning with a numeral, opens the sentence ({{xt|1-Naphthylamine is typically synthesized via the Felden{{shy}}shlager{{ndash}}Glocken{{shy}}spiel process}}) although this can usually be avoided by rewording ({{xt|Felden{{shy}}shlager{{ndash}}Glocken{{shy}}spiel is the process typically used in the synthesis of 1-naphthylamine}}).
** Not: {{!xt|There were many matches'''.''' 23 ended in a draw.}}
<!--* Avoid spelling out the year, unless it is part of a title: **Not: {{nowrap|{{!xt|Ninteen hundred and fifty had no elections}}{{ndash}}}}-->
** Use: {{xt|No elections were held in 1945 and 1950.}}
** Not: {{nowrap|{{!xt|1945 and 1950 had no elections.}}}} (Nor: {{nowrap|{{!xt|Nineteen forty-five and 1950 had no elections}}{{mdash}}}}comparable numbers near one another should all be written in words or all in figures.)
* In tables and infoboxes, quantities are expressed in figures ({{xt|Years in office:{{nbsp}}5}}); but numbers within a table's explanatory text and comments follow the general rule.
* Numbers in mathematical formulae are never spelled out ({{nobr|{{xt|3 < π < {{sfrac|22|7}}}}}} not {{nobr|{{!xt|three < pi < twenty-two sevenths}}}}), and "numbers as numbers" are rarely spelled out in other mathematical contexts ({{xt|the first three primes are 2, 3, and 5}} not {{!xt|the first three primes are two, three, and five}}; but {{xt|zero-sum game}} and {{xt|roots of unity}}).<!--There's probably still work to be done on the "in other mathematical contexts" bit-->
* Sport scores and vote tallies should be given as numerical figures ({{xt|a {{nowrap|25–7}} victory}}; {{xt|passed with 7 ayes, 2 nays, and 1 abstention}}, though {{xt|passed with 7 ayes, 2 nays, and no abstentions}} would be acceptable, instead of {{xtn|...{{nbsp}}0 abstentions}}).
* Comparable values near one another should be all spelled out or all in figures, even if one of the numbers would normally be written differently: {{xt|patients' ages were five, seven, and thirty-two}} or {{xt|ages were{{nbsp}}5, 7, and{{nbsp}}32}}, but not {{!xt|ages were {{nobr|five, seven, and 32}}}}.<!--example using ages was chosen specifically, since questions about how to represent ages come up perennially-->
**Similar guidance applies where "mixed units" are used to represent a single value (as is often done with time durations, and in the imperial and US customary systems): {{xt|{{nobr|5 feet 11 inches}} tall}}; {{xt|{{nobr|five feet eleven inches}} tall}}; {{xt|{{nobr|3 minutes 27 seconds}}}}; {{xt|{{nobr|three minutes twenty-seven seconds}}}}.
* Adjacent quantities not comparable should ideally be in {{em|different formats:}} {{nobr|{{xt|twelve 90-minute volumes}}}} or {{nobr|{{xt|12 ninety-minute volumes}}}}, not {{nobr|{{!xt|12 90-minute volumes}}}} or {{nobr|{{!xt|twelve ninety-minute volumes}}}}.
** Avoid awkward juxtapositions: {{xt|On February 25, 2011, twenty-one more were chosen}}, not {{nobr|{{!xt|On February 25, 2011, 21 more were chosen}}}}.
* Sometimes figures and words carry different meanings; for example, {{xt|Every locker except one was searched}} implies there is a single exception (without specifying which), while {{xt|Every locker except{{nbsp}}1 was searched}} implies that locker number{{nbsp}}1 was the only locker not searched.
* Proper names, technical terms, and the like are never altered: ],{{nbsp}} ],{{nbsp}} ],{{nbsp}} ],{{nbsp}} '']'',{{nbsp}} ],{{nbsp}} ],{{nbsp}} '']'',{{nbsp}} ],{{nbsp}} ],{{nbsp}} '']'',{{nbsp}} "]".
* Figures as figures: Use a figure when the figure itself (its ], shape, etc.) is meant: {{xt|a figure-8 pattern}}; {{xt|in the shape of the numeral ''6''}}. {{crossref|(See {{section link|Misplaced Pages:Manual of Style/Text formatting#Words as words}}.)}}
* Only figures are used with unit {{em|symbols}} ({{xt|12 min}} not {{!xt|twelve min}}); but figures or words may be used with unit {{em|names}} ({{xt|12 minutes}} or {{xt|twelve minutes}}), subject to the provisions above.


'''Other numbers'''
{{shortcut|MOS:ORDINAL|WP:ORDINAL}}<!--positioned before (rather than after) section in question to avoid crash of shortcut boxes when sections are short-->
* Other numbers are given in numerals ({{xt|3.75}}, {{xt|544}}) or in forms such as {{xt|21{{nbsp}}million}} (or ''billion'', ''trillion'', etc.{{snd}}but rarely ''thousand'' or ''hundred''). Markup: {{nowrap|<code><nowiki>21{{nbsp}}million</nowiki></code>}}
** ''Billion'' and ''trillion'' are understood to represent their ] values of 10<sup>9</sup>{{nbsp}}(1,000,000,000) and 10<sup>12</sup>{{nbsp}}(1,000,000,000,000), respectively. Keep this in mind when translating articles from non-English or older sources.
** {{xt|M}} (unspaced, capitalized) or {{xt|bn}} (unspaced), respectively, may be used for "million" or "billion" after a number, when the word has been spelled out at the first occurrence ({{xt|Her estate of &pound;61{{nbsp}}million was split among her husband (&pound;1M), her son (&pound;5M), her butler (&pound;10M), and her three Weimaraners (&pound;15M each).}}).<!--This needs to be coordinated with text in units tables re nonuse of M (for 1000) MM, etc.-->
** SI prefixes and symbols, such as {{xtn|mega-}}{{nbsp}}({{xtn|M}}), {{xtn|giga-}}{{nbsp}}({{xtn|G}}) and {{xtn|tera-}}{{nbsp}}({{xtn|T}}), should be used only with units of measure as appropriate to the field and not to express large quantities in other contexts. Examples of misuse: {{!xt|In a population of 1.3G{{nbsp}}people, 300{{nbsp}}megadeaths would be expected.}}
** Sometimes, the ] used in an article may suggest the use of a numbering system other than the Western thousands-based system. For example, the ] is conventionally used for certain things (especially monetary amounts) in ]. This is discouraged in Misplaced Pages articles by {{section link|WP:Manual of Style#Opportunities for commonality}}.
*** When it is done anyway, for contextually important reasons, link the first spelled-out instance of each quantity (e.g. <code><nowiki>]</nowiki></code>, which yields: ]). If no instances are spelled out, provide a note after the first instance, directing the reader to the article about the numbering system.
*** Provide a conversion to Western numbers for the first instance of each quantity (For Indian figures, the templates {{tlx|lakh}} and {{tlx|crore}} may be used for this purpose), and provide conversions for subsequent instances if they do not overwhelm the content of the article. For example, write {{xt|three ] (thirty million)}}. When converting a currency amount, use the exchange rate that applied at the time being written about; the {{tlx|FXConvert}} template can be used for this purpose, or specialized templates for a currency such as {{tlx|INRConvert}} (for Indian Rupees) or {{tlx|KRWConvert}} (for Korean Won) can be used.
*** Group digits in Western thousands-based style (e.g., {{xt|30,000,000}}; not {{!xt|3,00,00,000}}); {{crossref|see {{section link||Delimiting (grouping of digits)}}, below}}.
*** An article's variety of English does not uniquely determine its formatting of numbers. Other considerations{{snd}}such as conventions used in mathematics, science, and engineering{{snd}}may also apply. In general, choice and order of formats and conversions is a matter of editorial discretion and consensus at the article.

{{shortcut|MOS:ORDINAL}}<!--Positioned before (rather than after) section in question to avoid crash of shortcut boxes when sections are short.-->


===Ordinals=== ===Ordinals===
* {{anchor|1st}}] suffixes (''st'', ''nd'', ''rd'', ''th'') are not ]ed ({{xt|123rd}} and {{xt|496th}}, not {{!xt|123<sup>rd</sup>}} nor {{!xt|496<sup>th</sup>}}).
* ]s are normally written with ]s (without suffix i.e. {{xt|Elizabeth II}} not {{!xt|Elizabeth IInd}}).
* Do not use a dot ({{!xt|.}}) or the ordinal mark ({{!xt|&#186;}}) to indicate ordinals.


{{anchor|1st|1ST}}
===Fractions===
{{redirect|MOS:1ST|the guideline on the first sentence in articles|MOS:FIRST}}
{{shortcut|MOS:FRAC}}
* The general principles set out in {{section link||Numbers as figures or words}} apply to ordinals. In particular, do not start a sentence with a figure, and generally use {{xt|first}} through {{xt|ninth}}, not {{!xt|1st}} through {{!xt|9th}}, for single-digit ordinals.
* Spelled-out fractions are hyphenated: {{xt|seven-eighths}}.
* In "suffix" forms, use two-letter suffixes: {{xt|1st, 2nd, 3rd, 4th}} and so on ({{xt|2nd{{nbsp}}Battalion}} not {{!xt|2d{{nbsp}}Battalion}}). Do not superscript (e.g. {{!xt|123<sup>rd</sup>}}).
* Where numerator and denominator can each be expressed in one word, a fraction is usually ] (e.g. {{xt|a two-thirds majority}}; {{nbsp}}{{xt|moved one-quarter mile}}); use figures if a fraction appears with a symbol (e.g. {{xt|{{frac|1|4}}{{nbsp}}mi}}{{mdash}}''markup:'' <code>{{]|1|4}}&amp;nbsp;mi</code>, not {{!xt|a quarter of a mi}} or {{!xt|one-quarter mi}}).
* Do not use ordinals for dates (see ]).
* ] are usually given in figures, unspaced (not {{!xt|Fellini's film ''8{{nbsp}}{{frac|1|2}}''}} or {{!xt|''8-{{frac|1|2}}''}} but {{xt|Fellini's film ''{{frac|8|1|2}}''}}{{mdash}}''markup:'' <code><nowiki>{{frac|8|1|2}}</nowiki></code>). In any case the integer and fractional parts should be consistent (not {{!xt|nine and{{nbsp}}{{frac|1|2}}}}).
* In English text, do not use a dot ({{!xt|.}}) or the ] ({{!xt|º}}). The masculine {{xt|º}} or feminine {{xt|ª}} ordinal indicator is acceptable in names, quotations, etc. from languages that conventionally use it. An Italian example: {{xt|{{lang|it|313º Gruppo Addestramento Acrobatico}}}} not {{!xt|313º Acrobatic Training Group}} or {{!xt|the 313º}}. Use HTML markup for languages that do not have a special character but conventionally use a superscript, like {{xt|{{lang|fr|2<sup>e</sup>}}}} in French.
* ]s are normally written with ASCII ]s (without suffix, e.g. {{xt|Elizabeth II}} not {{!xt|Elizabeth IInd}} or {{!xt|Elizabeth 2nd}}).

===Number ranges===

{{shortcut|MOS:NUMRANGE|MOS:PAGERANGE}}

Like {{crossref|]}}, number ranges and page ranges should state the full value of both the beginning and end of the range, separated by an ]: {{xt|pp.{{nbsp}}1902{{ndash}}1911}} or {{xt|entries{{nbsp}}342{{ndash}}349}}. Except within quotations, avoid abbreviated forms such as {{!xt|1902{{ndash}}11}} or {{!xt|342{{ndash}}9}}, which are not understood universally, are sometimes ambiguous, and can cause inconsistent metadata to be created in citations.

===Sport scores, vote tallies, etc.===
{{shortcut|MOS:VOTE|MOS:SCORES}}

Sport scores, vote tallies, or other presentations that juxtapose two opposing quantities use an unspaced en dash:
*{{xt|Smith beat Jones {{nowrap|7{{ndash}}3}}.}}
*{{xt|Polls predicted Alice would defeat Bob {{nowrap|74{{ndash}}20}} percent, with 6 percent undecided.}}
To avoid potential line breaks, use {{tlx|nowrap}} around the entire score construction, or use {{tlx|nbnd}} instead of {{tlx|ndash}}.

===Singular versus plural===

* Nouns following ] are singular ({{xt|took {{frac|4}} dose}};{{nbsp}} {{xt|net change was −{{frac|2}} point}};{{nbsp}} {{xt|{{frac|3|2}} dose}}).
* Nouns following ]s are plural ({{xt|1{{frac|1|2}} doses}};{{nbsp}} {{xt|another 4{{frac|3|4}} miles}}).
* Nouns following the lone, unsigned digit 1 (one) are singular, but those following other decimal numbers (i.e. base-10 numbers not involving fractions) are plural ({{xt|increased 0.7 percentage points}};{{nbsp}} {{xt|365.25{{nbsp}}days}};{{nbsp}} {{xt|paid 5 dollars per work hour, 1 dollar per travel hour, 0 dollars per standby hour}};{{nbsp}} {{xt|increased by 1{{nbsp}}point}} but {{xt|net change +1{{nbsp}}points}};{{nbsp}} {{xt|net change &minus;1{{nbsp}}points}};{{nbsp}} {{xt|net change 1.0{{nbsp}}points}}).
* The same rules apply to numbers given in words ({{xt|one dose}};{{nbsp}} {{xt|one and one-half doses}};{{nbsp}} {{xt|zero dollars}};{{nbsp}} {{xt|net change of negative one points}}).

===Fractions and ratios<span id="Fractions"></span>===

{{shortcut|MOS:FRAC|MOS:RATIO}}
* Where numerator and denominator can each be expressed in one word, a fraction is usually ] (e.g. {{xt|a two-thirds majority}}; {{nbsp}}{{xt|moved one-quarter mile}}); use figures if a fraction appears with a unit symbol (e.g. {{xt|{{frac|1|4}}{{nbsp}}mi}} (markup: <code>{{tlf|frac|1|4}}&amp;nbsp;mi</code>), not {{!xt|a quarter of a mi}} or {{!xt|one-quarter mi}}). A common exception is a series of values: {{xt|The distances were {{frac|1|1|4}}, {{frac|2|3}} and {{frac|1|2}} mile, respectively}}.
* ] may be given in figures or words (perhaps applying the guidance ] to the integer part). If given in figures, they are unspaced (not {{!xt|Platform 9{{nbsp}}{{frac|3|4}}}} or {{!xt|Platform 9-{{frac|3|4}}}} but {{xt|Platform {{frac|9|3|4}}}} (markup: <code><nowiki>{{frac|9|3|4}}</nowiki></code>)). In any case the integer and fractional parts should be consistent (not {{!xt|Platform nine and{{nbsp}}{{frac|3|4}}}}).
* Metric (SI) measurements generally use decimals, not fractions ({{xt|5.25{{nbsp}}mm}}, not {{!xt|5{{frac|1|4}}{{nbsp}}mm}}). * Metric (SI) measurements generally use decimals, not fractions ({{xt|5.25{{nbsp}}mm}}, not {{!xt|5{{frac|1|4}}{{nbsp}}mm}}).
* Non-metric (imperial and US customary) measurements may use fractions or decimals ({{xt|5{{frac|1|4}}{{nbsp}}inches}};{{nbsp}}{{xt|5.25{{nbsp}}inches}}); the practice of reliable sources should be followed, and within-article consistency is desirable. * Non-metric (imperial and US customary) measurements may use fractions or decimals ({{xt|5{{frac|1|4}}{{nbsp}}inches}};{{nbsp}}{{xt|5.25{{nbsp}}inches}}); the practice of reliable sources should be followed, and within-article consistency is desirable.
* In science and mathematics articles mixed numbers are rarely used (not {{!xt|1{{frac|1|3}} times the original voltage}}, but {{xt|4/3 the original}}) and use of {{tlx|frac}} is discouraged in favor of one of these styles: * In science and mathematics articles, mixed numbers are rarely used (use {{xt|{{sfrac|4|3}} the original voltage}} rather than {{!xt|1{{sfrac|1|3}} times the original voltage}}). The use of {{tlx|frac}} ]; instead use one of these styles:
: &nbsp; &bull; &nbsp; <math>\textstyle\frac{1}{2}</math>{{nbsp}} ''Markup:'' <code><]>\textstyle\frac{1}{2}<nowiki></math></nowiki></code> ** <math>\textstyle\frac{1}{2}</math> (markup: <code><]>\textstyle\frac{1}{2}<nowiki></math></nowiki></code>)
: &nbsp; &bull; &nbsp; {{xt|{{sfrac|2}}}}{{nbsp}} ''Markup:'' <code>{{]|2}}</code> ** {{xt|{{sfrac|1|2}}}} (markup: {{tlx|sfrac|1|2}})
: &nbsp; &bull; &nbsp; {{xt|1/2}}{{nbsp}} ''Markup:'' <code>1/2</code> ** {{xt|1/2}} (markup: <code>1/2</code>)
* Do not use special characters such as &frac12; (''Deprecated markup:'' <code>&amp;frac12;</code> or <code>&amp;#189;</code>). * Do not use ] characters such as {{!xt|½}} (deprecated markup: {{!mxt|&amp;frac12;}} or {{!mxt|&amp;#189;}}).{{efn|Some precomposed fractions may not work with screen readers, and not all fractions are available precomposed.}}
** Except: If ¼, ½, and ¾{{efn|These three characters are in ] and work in screen readers.}} are the only fractions needed, they may be used in an article, or category name, maintaining typographical consistency within an article where possible. (Examples: ], ], ], ].) <!-- In case consensus changes or there is an usual corner case, {{DISPLAYTITLE:{{NAMESPACE}}:Ranma <sup>1</sup>/<sub>2</sub>}} works for e.g. ]. -- Beland -->
* ] such as ''th'' should not be used with fractions expressed in figures (not {{!xt|each US state has 1/50th of the ] votes}}, but {{xt|one-fiftieth of the ] votes}}).
** For other fractions, where templates cannot be used due to technical limitations, use the ASCII representation with spaces. For example, ].
* Nouns following ] are singular ({{xt|He took {{frac|4}} dose}},{{nbsp}} {{xt|net change in score was &minus;{{frac|2}} point}},{{nbsp}} {{xt|{{frac|3|2}} dose}}).
* Ordinal suffixes such as {{xtn|-th}} should not be used with fractions expressed in figures (not {{!xt|each US state has 1/50th of the ] votes}}; {{!xt|1/8th mile}}, but {{xt|one-fiftieth of the ] votes}}; {{xt|1/8 mile}}; {{xt|one-eighth mile}}).
* Nouns following mixed numbers are plural ({{xt|suicide victim knew even 1{{frac|1|2}} doses could be fatal}},{{nbsp}} {{xt|vessel continued another 4{{frac|2}} nautical miles}}).
* For dimensionless ratios (i.e. those without accompanying units), place a colon between integers, or place ''to'' between numbers-as-words: {{ xt|favored by a 3:1 ratio}} or {{nobr|{{xt|a three-to-one ratio}}}}, not {{nobr|{{!xt|a 3/1 ratio}}}} or {{nobr|{{!xt|a 3{{ndash}}1 ratio}}.}} The same style is used to express ] in sport, gambling, and other statistical predictions.
** Use a colon (spaced) when one or more decimal points is present {{nobr|({{ xt|a 3.5{{nbsp}}:{{nbsp}}1 ratio}} (markup:}} {{nobr|<code>a 3.5&amp;nbsp;:&amp;nbsp;1 ratio</code>)).}}
** Do not use the colon form where units are involved ({{!xt|dissolve using a {{nobr|3 ml : 1 g ratio}}}}){{mdashb}}instead see ''ratios'' section of table at ], below.
{{see also|Misplaced Pages:Manual of Style/Mathematics#Fractions}}

===Decimals<span id="Decimal points"></span>===

{{shortcut|MOS:DECIMAL}}
* Use a period/full point (<code>.</code>) as the ], {{em|never}} a comma: {{xt|6.57}}, not {{!xt|6,57}}.
* Numbers between −1 and +1 require a leading zero ({{xt|0.02}}, not {{!xt|.02}}); exceptions are sporting performance averages ({{xt|.430 ]}}) and conventional terms such as {{xt|.22{{nbsp}}caliber}}.
* Although repeating digits may be indicated with an ] (e.g. {{nowrap|<code><nowiki>14.31{{overline|28}}</nowiki></code>}} gives {{xt|14.31{{overline|28}}}}), users of screen readers will not hear any indication of the overbar. Apart from in mathematics articles, consider rounding to a reasonable resolution instead (e.g. a ] {{xt|1=≈£0.00052}} not {{!xt|1=£0.0005208{{overline|3}}}}, an ] {{xt|1=≈0.333 ]s}} not {{!xt|1=0.{{overline|3}} ]s}}), or showing initial repeats before the overbar (e.g. 0.33{{overline|3}}). If overbars are used, consider explaining the notation on first use. Do not write e.g. {{nobr|{{!xt|14.31(28)}}}} because it resembles ].


===Grouping of digits===
===<span id="Decimal points" />Decimals===
<span id="Delimiting (grouping of digits)"></span><span id="Grouping of digits"></span>
{{shortcut|WP:DECIMAL|MOS:DECIMAL}}
{{shortcut|MOS:DIGITS}}
* A period/full stop (''never'' a comma) is used as the decimal point ({{xt|6.57}}, not {{!xt|6,57}}).
* Numbers between −1 and +1 require a leading zero ({{xt|0.02}}, not {{!xt|.02}}); exceptions are sporting performance averages ({{xt|.430 ]}}) and commonly used terms such as {{xt|.22{{nbsp}}caliber}}.
* Nouns following a number expressed as a decimal are plural ({{xt|averaging 0.7 years}}).
* Indicate repeating digits with an ] e.g. {{nowrap|<code><nowiki>14.31{{overline|28}}</nowiki></code>}} gives {{xt|14.31{{overline|28}}}}. (Consider explaining this notation on first use.) Do not write e.g. {{nobr|{{!xt|14.31(28)}}}} because it resembles notations for {{section link||Uncertainty}}.


* In general, digits should be grouped and separated either by commas or by narrow gaps ({{em|never}} a period/full point).
====<span id="Delimiting (grouping of digits)" />Grouping of digits====
** Grouping with commas
{{shortcut|WP:DIGITS|MOS:DIGITS}}
*** Left of the decimal point, five or more digits are grouped into threes separated by commas (e.g. {{xt|12,200}}; {{xt|255,200{{nbsp}}km}}; {{xt|8,274,527th}}; {{xt|{{frac|86,400}}}}).
* Digits should be grouped and separated either by commas or narrow gaps (''never'' a period/full stop).
*** Numbers with exactly four digits left of the decimal point may optionally be grouped (either {{xt|1,250}} or {{xt|1250}}), consistently within any given article.
:; Grouping with commas
*** Do not use commas to the right of the decimal point, or with numbers not in base 10.
:* Left of the decimal point, five or more digits are grouped into threes separated by commas (e.g. &nbsp;{{xt|12,200}}, &nbsp;{{xt|255,200&nbsp;km}}, &nbsp;{{xt|8,274,527th}}, &nbsp;{{xt|{{frac|86,400}}}}).
*** Markup: {{tlc|]}} produces this formatting.
:* Numbers with exactly four digits left of the decimal point may optionally be grouped (either &nbsp;{{xt|1,250}} &nbsp;or &nbsp;{{xt|1250}}), provided that this is consistent within each article.
** Grouping with narrow gaps
:* When commas are used left of the decimal point, digits right of the decimal point are not grouped (i.e. should be given as an unbroken string).
*** Digits are grouped both sides of the decimal point (e.g. {{xt|{{val|6543210.123456}}}}; {{xt|{{val|520.01234|u=degC}}}}; {{xt|{{sfrac|{{val|101325}}|760}}}}).
:* ''Markup:'' {{tlc|]}} produces this formatting.
*** Digits are generally grouped into threes. Right of the decimal point, {{em|usual}} practice is to have a final group of four in preference to leaving an "orphaned" digit at the end ({{xt|{{val|99.1234567}}}}, but {{xt|{{gaps|99.123|456|7}}}} would also be acceptable). In mathematics-oriented articles long strings may be grouped into fives (e.g. {{xt|{{gaps|3.14159|26535|89793|23846|...}}}}).
:; Grouping with narrow gaps
*** This style is especially recommended for articles related to science, technology, engineering or mathematics, though in these contexts there may be cases in which grouping confuses rather than clarifies. (For example, for fractions written in horizontal format, adding spaces to a fraction like 123456/127 would cause it to be misread as 123{{sfrac|456|127}} or 1{{sfrac|23456|127}}.)
:* Digits are grouped both sides of the decimal point (e.g. &nbsp;{{xt|{{val|6543210.123456}}}}, &nbsp;{{xt|{{val|520.01234|u=degC}}}}, &nbsp;{{xt|{{sfrac|{{val|101325}}|760}}}}).
*** Markup: Templates {{tlx|val}} or {{tlx|gaps}} may be used to produce this formatting. Note that use of {{em|any}} space character as a separator<!--Word included here on purpose, for in-page searching.--> in numbers, including non-breaking space, is problematic for ]s. {{crossref|(See {{section link||Non-breaking spaces}}.)}} Screen readers read out each {{em|group}} of digits as separate numbers (e.g. <code>30{{tl|thin space}}000</code> is read as "thirty zero zero zero"). The output of {{tlx|val}} and {{tlx|gaps}} is compatible with screen readers.
:* Digits are generally grouped into threes. Right of the decimal point, ''usual'' practice is to have a final group of four instead of a lone digit (e.g. &nbsp;{{xt|{{val|99.1234567}}}} &nbsp;or &nbsp;{{xt|{{gaps|99.123|456|7}}}}). In mathematics-oriented articles long strings may be grouped into fives (e.g. &nbsp;{{xt|{{gaps|3.14159|26535|89793|23846|...}}}}).
:* This style is especially recommended for articles related to science, technology, engineering or mathematics.
:* ''Markup:'' Templates {{tlx|val}} or {{tlx|gaps}} may be used to produce this formatting. Note that use of ''any'' space character in numbers, including non-breaking space, is problematic for ]s. (See ]) Screen readers read out each ''group'' of digits as separate numbers (e.g. &nbsp;<code>30&amp;thinsp;000</code>&nbsp; is read as "thirty zero zero zero".)
* Delimiting style should be consistent throughout a given article. * Delimiting style should be consistent throughout a given article.
:* Either use commas or narrow gaps, but not both in the same article. ** Either use commas or narrow gaps, but not both in the same article.
:* Either group the thousands in a four-digit number or do not, but not mixed use in the same article. ** Either group the thousands in a four-digit number or do not, but not mixed use in the same article.
:* However, grouping by threes and fives may coexist. ** However, grouping by threes and fives may coexist.
* An exception is made for four-digit page numbers or four-digit calendar years. These should never be grouped (not &nbsp;{{!xt|sailed in 1,492}}, &nbsp;though &nbsp;{{xt|dynasty collapsed around 10,400&nbsp;BC}} &nbsp;or &nbsp;{{xt|by {{val|13727|u=AD}}, the Earth's axial precession will have made Vega the northern pole star}}). * Four-digit page numbers and four-digit calendar years should never be grouped (not {{!xt|sailed in 1,492}}, but {{xt|dynasty collapsed around 10,400{{nbsp}}BC}} or {{xt|by {{val|13727|u=AD}}, Vega will be the northern pole star}}).


===Percentages=== ===Percentages===

{{shortcut|MOS:PERCENT|WP:PERCENT|WP:%}}
{{shortcut|MOS:PERCENT|MOS:%}}
* In the body of non-scientific/non-technical articles, ''percent'' (American English) or ''per cent'' (British English) are commonly used: {{xt|10 percent}}; {{xt|ten percent}}; {{xt|4.5 per cent}}. Ranges are written {{xt|ten to twelve per cent}} or {{xt|ten to twelve percent}}, not {{!xt|ten{{ndash}}twelve per cent}} or {{!xt|ten to twelve %}}.
* In the body of scientific/{{zwsp}}technical articles, and in '''tables and infoboxes''' of any article, the symbol ''%'' (unspaced) is more common: {{xt|71%}}, not {{!xt|71 %}} or {{!xt|three %}}. Ranges: {{xt|10{{ndash}}12%}}, not {{!xt|10%{{ndash}}12%}} or {{!xt|10 to 12%}}. * Throughout scientific/{{zwsp}}technical articles, and in tables and infoboxes in ''any'' article, the symbol <code>%</code> is generally preferred. Omit space ({{xt|3%}}, not {{!xt|3{{nbsp}}%}}), and do not use mixed forms such as {{!xt|three{{nbsp}}%}}.
* The body{{efn|name=body}} of non-scientific/{{zwsp}}non-technical articles may use either the <code>%</code> symbol or the word(s) {{xtn|percent}} (American English) or {{xtn|per{{nbsp}}cent}} (British English): {{xt|10 percent}}; {{xt|ten percent}}; {{xt|4.5 per cent}}.
* Ranges are written {{xt|10{{ndash}}12%}}, {{xt|ten to twelve per cent}}, or {{xt|ten to twelve percent}}; not {{!xt|ten{{ndash}}twelve per cent}}, {{!xt|10%{{ndash}}12%}}, or {{nobr|{{!xt|10 to 12%}}}}.
* When expressing the difference between two percentages, do not confuse a percentage change with a change in ]s. * When expressing the difference between two percentages, do not confuse a percentage change with a change in ]s.


===<span id="Scientific notation, engineering notation, and uncertainty" />Scientific and engineering notation=== ===Scientific and engineering notation<span id="Scientific notation, engineering notation, and uncertainty"></span>===
{{Shortcut|MOS:SCIENGNOTATION|MOS:10^X}}
* ] always has a single nonzero digit to the left of the point: not {{!xt|{{val|60.22|e=22}}}}, but {{xt|{{val|6.022|e=23}}}}.
* ] is similar, but adjusted so that the exponent is a multiple of three: {{xt|{{val|602.2|e=21}}}}. * ] always has a single nonzero digit to the left of the point: not {{!xt|{{val|60.22|e=22}}}}, but {{xt|{{val|6.022|e=23}}}}.
* ] is similar, but with the exponent adjusted to a multiple of three: {{xt|{{val|602.2|e=21}}}}.
* Avoid mixing scientific and engineering notations ({{!xt|A {{val|2.23|e=2|u=m2}} region covered by {{val|234.0|e=6|u=grains of sand}}}}).
* Avoid mixing scientific and engineering notations: {{!xt|A {{val|2.23|e=2|u=m2}} region covered by {{val|234.0|e=6|u=grains of sand}}}}.
* In a table column (or other presentation) in which all values can be expressed with a single power of 10, consider giving e.g. {{xt|{{e|7}}}} once in the column header, and omitting it in the individual entries. (''Markup:''<code><nowiki>{{e|7}}</nowiki></code>)
* In a table column (or other presentation) in which all values can be expressed with a single power of 10, consider giving e.g. {{xt|{{e|7}}}} once in the column header, and omitting it in the individual entries. (Markup: <code><nowiki>{{e|7}}</nowiki></code>)
* In both notations, the number of digits indicates the precision. For example, {{xt|{{val|5|e=3}}}} means rounded to the nearest thousand; {{xt|{{val|5.0|e=3}}}} to the nearest hundred; {{xt|{{val|5.00|e=3}}}} to the nearest ten; and {{xt|{{val|5.000|e=3}}}} to the nearest unit. * In both notations, the number of digits indicates the precision. For example, {{xt|{{val|5|e=3}}}} means rounded to the nearest thousand; {{xt|{{val|5.0|e=3}}}} to the nearest hundred; {{xt|{{val|5.00|e=3}}}} to the nearest ten; and {{xt|{{val|5.000|e=3}}}} to the nearest unit.


''Markup:'' {{tlx|Val}} and {{tlx|e}} may be used to format exponential notation. Markup: {{tlx|val}} and {{tlx|e}} may be used to format exponential notation.

===Uncertainty and rounding <span id="Uncertainty"></span> <span id="Large numbers"></span>===


===Uncertainty and rounding <span id="Uncertainty" /> <span id="Large numbers" />===
{{shortcut|MOS:UNCERTAINTY|MOS:LARGENUM}} {{shortcut|MOS:UNCERTAINTY|MOS:LARGENUM}}
* Where explicit uncertainty information (such as a "]") is available and appropriate for inclusion, it may be written in various ways: * Where explicit uncertainty information (such as a ]) is available and appropriate for inclusion, it may be written in various ways:
: &nbsp; &bull; &nbsp;{{xt|(1.534 ± 0.035) × 10<sup>23</sup> m}} ** {{xt|(1.534 ± 0.035) × 10<sup>23</sup> m}}
: &nbsp; &bull; &nbsp;{{xt|12.34{{nbsp}}m<sup>2</sup> ± 5%}} (not used with scientific notation) ** {{xt|12.34{{nbsp}}m<sup>2</sup> ± 5%}} (not used with scientific notation)
: &nbsp; &bull; &nbsp;{{xt|15.34 {{su|p=+0.43|b=−0.23}} × 10<sup>23</sup> m}} ** {{xt|15.34 {{su|p=+0.43|b=−0.23}} × 10<sup>23</sup> m}}
: &nbsp; &bull; &nbsp;{{xt|1.604(48) × 10<sup>−4</sup> J}} (equivalent to {{xt|(1.604 ± 0.048) × 10<sup>−4</sup> J}})<ref>The number in parentheses is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result see </ref> ** {{xt|1.604(48) × 10<sup>−4</sup> J}} (equivalent to {{xt|(1.604 ± 0.048) × 10<sup>−4</sup> J}}){{efn|1=The number in parentheses in a construction like {{xt|1.604(48) × 10<sup>−4</sup> J}} is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.<ref>{{cite web |url= http://www.physics.nist.gov/cgi-bin/cuu/Info/Constants/definitions.html |title=Fundamental Physical Constants: Standard Uncertainty and Relative Standard Uncertainty |work=The NIST Reference on Constants, Units, and Uncertainty |date=June 25, 2015<!--Last updated, according to https://physics.nist.gov/cuu/Constants/bibliography.html --> |publisher=US ] |access-date=December 12, 2017}}</ref>}}
: &nbsp; &bull; &nbsp;{{xt|Polls estimated Jones's share of the vote would be 55%, give or take about 3%}} ** {{xt|Polls estimated Jones's share of the vote would be 55 percent, give or take about 3 percent}}
:''Markup:'' {{tlx|+-}}, {{tlx|su}}, and {{tlx|val}} may be used to format uncertainties. ** Markup: {{tlx|+-}}, {{tlx|su}}, and {{tlx|val}} may be used to format uncertainties.
* Where explicit '''uncertainty is unavailable''' (or is unimportant for the article's purposes) round to an appropriate number of ]s; the precision presented should usually be conservative. Precise values (often given in sources for formal or matter-of-record reasons) should be used only where stable and appropriate to the context, or significant in themselves for some special reason. * Where explicit {{em|uncertainty is unavailable}} (or is unimportant for the article's purposes), round to an appropriate number of ]s; the precision presented should usually be conservative. Precise values (often given in sources for formal or matter-of-record reasons) should be used only where stable and appropriate to the context, or significant in themselves for some special reason.
: &nbsp; &bull; &nbsp; {{xt|The speed of light is defined to be 299,792,458{{nbsp}}m/s}} ** {{xt|The speed of light is defined to be 299,792,458{{nbsp}}m/s}}
:: ''but'' {{xt|Particle velocities eventually reached almost two-thirds the 300-million-metre-per-second speed of light}} ** {{em|but}} {{xt|Particle velocities eventually reached almost two-thirds the 300-million-metre-per-second speed of light.}}
** {{xt|checks worth $250 (equivalent to $1,800 in 2016)}} (not {{!xt|$1,845.38 in 2016}})
: &nbsp; &bull; &nbsp; {{xt|The city's 1920 population was 667,000}} (not {{!xt|population was 666,666}}{{mdashb}}an official figure unlikely to be accurate at full precision)
** {{xt|The city's 1920 population was 10,000}} (not {{!xt|population was 9,996}}{{snd}}an official figure unlikely to be accurate at full precision)
:: ''but'' {{xt|The town was ineligible because its official census figure (9,996) fell short of the statutory minimum of ten thousand }} (unusual case in which the full-precision official population figure is helpful to readers)
** {{em|but}} {{xt|The town was ineligible because its official census figure (9,996) fell short of the statutory minimum of ten thousand }} (unusual case in which the full-precision official figure is truly informative)
: &nbsp; &bull; &nbsp; {{xt| The accident killed 337 passengers and crew, and three airport workers }} (likely that accurate and precise figures were determined)
** {{xt| The accident killed 337 passengers and crew, and 21 people on the ground }} (likely that accurate and precise figures were determined)
: &nbsp; &bull; &nbsp; {{xt| At least 800 persons died in the ensuing mudslides }} (unlikely that any precise number can be accurate, even if an official figure is issued)
** {{xt| At least 800 persons died in the ensuing mudslides }} (unlikely that any precise number can be accurate, even if an official figure is issued)
:: ''or'' {{xt| Officials listed 835 deaths, but the Red Cross said dozens more may have gone unreported }} (in reporting conflicting information, give detail sufficient to make the contrast intelligible)
** {{em|or}} {{xt| Officials listed 835 deaths, but the Red Cross said dozens more may have gone unreported }} (in reporting conflicting information, give detail sufficient to make the contrast intelligible)
: &nbsp; &bull; &nbsp; {{xt|The jury's award was $8.5{{nbsp}}million{{nbsp}}...}} (where the actual figure was $8,462,247.63) {{xt| ...{{snd}}reduced on appeal to $3,000,001 (one dollar in ], the remainder in ])}}
** {{xt|The jury's award was $8.5{{nbsp}}million}} (not {{!xt|$8,462,247.63}}). {{xt|The appeals court reduced this to $3,000,001 (one dollar in actual damages, the remainder in punitive damages).}}
* The number of decimal places should be consistent within a list or context ({{xt|The response rates were 41.0 and 47.4 percent, respectively}}, not {{!xt|41 and 47.4 percent}}), unless different precisions are actually intended. * The number of decimal places should be consistent within a list or context ({{xt|The response rates were 41.0 and 47.4 percent, respectively}}, not {{!xt|41 and 47.4 percent}}), unless different precisions are actually intended.
* It may sometimes be appropriate to note the ''lack'' of uncertainty information, especially where such information is normally provided and necessary for full interpretation of the figures supplied. * It may sometimes be appropriate to note the {{em|lack}} of uncertainty information, especially where such information is normally provided and necessary for full interpretation of the figures supplied.
: &nbsp; &bull; &nbsp; {{xt|A local newspaper poll predicted 52% of the vote would go to Smith, but did not publish information on the uncertainty of this estimate}} ** {{xt|A local newspaper poll predicted 52 percent of the vote would go to Smith, but did not include information on the uncertainty of this estimate}}
* The {{tlx|undue precision}} template may be added to figures appearing to be overprecise. * The {{tlx|undue precision}} template may be added to figures appearing to be overprecise.
* Avoid using "approximately", "about", and similar terms with figures that have merely been approximated or rounded in a normal and expected way, unless the reader might otherwise be misled.
** {{xt|The tallest player was 6 feet 3 inches}} ({{nobr|not {{!xt|... about 6 feet 3 inches}}}}{{snd}}heights are conventionally reported only to the nearest inch, even though greater precision may be available in principle)<!--Please, no lectures about SI{{snd}}if you can give a parallel metric example please do so.-->
** {{em|but}} {{xt|The witness said the assailant was about 5 feet 8 inches tall}} ("about" because here the precise value is unknown, with substantial uncertainty)
* The reader may be assumed to interpret large round numbers ({{xt|100,000 troops}}) as approximations. Writing a quantity in words ({{xt|one hundred thousand troops}}), especially if the ] (''a''/''an'') is used instead of the word ''one'' ({{xt|a hundred thousand troops}}), can further emphasize its approximate nature.
* {{crossref|See {{section link||Unit conversions}} below for precision issues when converting units.}}


===Non–base-10 notations<span class="anchor" id="Non–base 10 notations"></span>===
* Avoid using "approximately", "about" and similar terms with figures that have merely been approximated or rounded in a normal and expected way, unless the reader might otherwise be misled.
: &nbsp; &bull; &nbsp; {{xt|The tallest player was 6 feet 3 inches}} ({{nobr|not {{!xt|... about 6 feet 3 inches}}}}{{mdashb}}heights are conventionally reported only to the nearest inch, even though greater precision may be available in principle)<!-- please, no lectures about SI -- if you can give a parallel metric example please do so-->
:: ''but'' {{xt|The witness said the assailant was about 5 feet 8 inches tall}} (''about'' because here the precise value is unknown, with substantial uncertainty)
* The reader may be assumed to interpret large round numbers ({{xt|100,000 troops}}) as approximations. Writing a quantity in words ({{xt|one hundred thousand troops}}) can further emphasize its approximate nature.


*See {{section link||Unit conversions}} below for precision issues when converting units.

===Non-]-10 notations===
{{shortcut|MOS:BASE|MOS:RADIX|MOS:BINARY|MOS:HEX}} {{shortcut|MOS:BASE|MOS:RADIX|MOS:BINARY|MOS:HEX}}
* In computer-related articles, use the ] prefixes <tt>0x</tt> (zero-ex) for hexadecimal and <tt>0</tt> (zero) for octal. For binary, use <tt>0b</tt>. <!-- Note that 0b is *not* a valid C prefix --> Explain these prefixes in the article's introduction or on first use. * In computer-related articles, use the prefix <code>0x</code> for hexadecimal and <code>0b</code> for binary,{{efn|1=The prefixes <code>0x</code> for hexadecimal and <code>0b</code> for binary have widespread support in systems programming languages including ], ], ], ] and ].}} unless there is a strong reason to use some other notation.{{efn|1=One such situation is with ] codepoints, which use <code>U+</code>; {{xt|U+26A7}}, not {{!xt|0x26A7}}.}} Explain these prefixes in the article's introduction or on first use.
* In all other articles, use <code>&lt;sub></code> to create subscripts: {{xt|137<sub>9</sub>}}, {{xt|241<sub>3</sub>}}. ''Markup:'' {{xt|137<nowiki><sub>9</sub></nowiki>}}, {{xt|241<nowiki><sub>3</sub></nowiki>}} * In all other articles, use {{tlx|base}}: {{base|137|9}}, {{base|201|3}}. Markup: <code><nowiki>{{base|137|9}}</nowiki></code>, <code><nowiki>{{base|201|3}}</nowiki></code>
* For bases above 10, use symbols conventional for that base (as seen in reliable sources) e.g. for ] use {{nobr|0{{ndash}}9A{{ndash}}F}}. * For ] above 10, use symbols conventional for that base (as seen in reliable sources) e.g. for ] use {{nobr|0{{ndash}}9 and A{{ndash}}F}}.
* For octal, use {{base|200|8}}. Avoid using a prefix unless it is needed for computer code samples, in which case explain the prefix on first use.


===Mathematical formulae===
== Units of measurement ==

{{Shortcut|WP:UNIT|WP:UNITS|WP:METRIC|WP:MEASUREMENT}}
{{Main|Misplaced Pages:Manual of Style/Mathematics}}

There are multiple ways to display mathematical formulae, covered in detail at {{section link|Misplaced Pages:Manual of Style/Mathematics#Typesetting of mathematical formulae}}. One uses special MediaWiki {{tag|math}} markup using ] syntax, which is capable of complex formulae; the other relies on conventionalized ] formatting of simple formulae.

The {{tag|math|o}} markup is displayed as a ] image by default. Logged-in users can optionally have it rendered in ], or in HTML (via ]); detailed instructions are at ].

].

==Units of measurement==

{{Shortcut|MOS:UNIT|MOS:UNITS|MOS:METRIC|MOS:MEASUREMENT}}


===Unit choice and order=== ===Unit choice and order===

Quantities are typically expressed using an appropriate "primary unit", displayed first, followed, when appropriate, by a conversion in parentheses e.g. {{xt|{{convert|200|km|mi}}}}.
For details on when and how to provide a conversion, see the section {{section link||Unit conversions}}. The choice of primary units depends on the circumstances, and should respect the principle of "]", where applicable: Quantities are typically expressed using an appropriate "primary unit", displayed first, followed, when appropriate, by a conversion in parentheses e.g. {{xt|{{convert|200|km|mi}}}}. For details on when and how to provide a conversion, see the section {{section link||Unit conversions}}. The choice of primary units depends on the circumstances, and should respect the principle of ], where applicable:
* In '''non-scientific articles with strong ties to the United States''', the primary units are ] (pounds, ], feet, inches, etc.)
* In '''most articles, including all scientific articles''', the primary units chosen will be ] units, ], or such other units as are conventional in reliable-source discussions of the article topic (such as ] (rpm) for angular speed, ]s for heights of horses, et cetera).
* In '''non-scientific articles with strong ties to the United Kingdom''', the primary units for most quantities are metric or other internationally used units,{{efn|1=If there is disagreement about the primary units used in a UK-related article, discuss the matter on the article talk-page or at ] (]). If consensus cannot be reached, refer to historically stable versions of the article and retain the units used in these as the primary units. Also note the ] of British publications (e.g. , under "Metric").}} except that:
* In '''non-scientific articles relating to the United States''', the primary units are ], e.g. {{xt|97{{nbsp}}pounds (44{{nbsp}}kg)}}.
** UK engineering-related articles, including those on bridges and tunnels, generally use the system of units in which the subject project was ] (but road distances are given in imperial units, with a metric conversion{{snd}}see next bullet);
* In '''non-scientific articles relating to the United Kingdom''', the primary units for most quantities are metric or other internationally used units,<ref name="UKmetricUnits">If there is disagreement about the primary units used in a UK-related article, discuss the matter on the article talk-page, at ], or both. If consensus cannot be reached, refer to historically stable versions of the article and retain the units used in these as the primary units. Note the ] of British publications such as ''The Times'' (see , under "Metric").</ref> except that:
** the primary units for distance/{{zwsp}}length, speed and fuel consumption are miles, miles per hour, and miles per imperial gallon (except for short distances or lengths, where miles are too large for practical use); ** the primary units for distance/{{zwsp}}length, speed and fuel consumption are ], miles per hour, and miles per imperial gallon (except for short distances or lengths, where miles are too large for practical use);
** the primary units for personal height and weight are feet{{zwsp}}/inches and stones/{{zwsp}}pounds; ** the primary units for personal height and weight are feet{{zwsp}}/inches and stones/{{zwsp}}pounds;
** imperial pints are used for quantities of draught beer/{{zwsp}}cider and bottled milk; ** imperial pints are used for quantities of draught beer/{{zwsp}}cider and bottled milk;
* In '''all other articles''', the primary units chosen will be ] units (such as kilograms), ], or such other units as are conventional in reliable sources discussing the article topic (such as ] (rpm) for ], ] for heights of horses, ], etc.)
** UK engineering-related articles, including those on bridges and tunnels, generally use the system of units that the topic was drawn-up in (but road distances are given in imperial units, with a metric conversion).
** the primary SI units for personal height and weight are centimetres and kilograms.


''Special considerations:'' {{em|Special considerations:}}
* Quantities set via definition (as opposed to measured quantities) should be given first in the units used in the definition, even if this makes the structure of presentation inconsistent: {{xt|During metrification, the speed limit was changed from 30{{nbsp}}miles per hour (48{{nbsp}}kilometers per hour) to 50{{nbsp}}km/h (31{{nbsp}}mph)}}. * Quantities set via definition (as opposed to measured quantities) should be given first in the units used in the definition, even if this makes the structure of presentation inconsistent: {{xt|During metrication, the speed limit was changed from 30{{nbsp}}mph (48{{nbsp}}km/h) to 50{{nbsp}}km/h (31{{nbsp}}mph)}}.
** This may benefit from a slightly non-standard structure, such as {{xt|...from 30{{nbsp}}miles per hour (about 48{{nbsp}}kilometers per hour) to 50{{nbsp}}km/h (about 31{{nbsp}}mph)}}. In this sort of case, using "about" can help make clear which is the statutory, exact value. ** Or use ''about'' to emphasize which is the statutory, exact value: {{xt|...from 30{{nbsp}}mph (about 48{{nbsp}}km/h) to 50{{nbsp}}km/h (about 31{{nbsp}}mph)}}.
* Nominal quantities (e.g. {{nowrap|"]"}} lumber) require consideration of whether the article is concerned with the item's actual dimensions or merely with its function. In some cases only the nominal quantity may suffice; in others it may be necessary to give the nominal size (often in non-SI units), the actual size in non-SI units, and the actual size in SI units. * Nominal quantities (e.g. {{xt|2{{nbsp}}×{{nbsp}}4}} ]) require consideration of whether the article is concerned with the item's actual dimensions or merely with its function. In some cases, the nominal quantity may suffice; in others it may be necessary to give the nominal size (often in non-SI units), the actual size in non-SI units, and the actual size in SI units.
* Whenever a conversion is used, ensure that the precision of the converted quantity in the article is comparable to the precision of the value given by the source (see {{section link||Unit conversions}}).<!--this passage might be unnecessary given the "Unit conversions" section below?--> * Whenever a conversion is given, the converted quantity's value should match the precision of the source {{crossref|(see {{section link||Unit conversions}})}}.
* Where the article's primary units differ from the units given in the source, the {{tlx|convert}} template's <code>|order=flip</code> flag can be used; this causes the ''original'' unit to be shown as secondary in the article, and the ''converted'' unit to be shown as primary.<!--an example would be very helpful here--> * Where the article's primary units differ from the units given in the source, the {{tlx|convert}} template's <code>|order=flip</code> flag can be used; this causes the {{em|original}} unit to be shown as secondary in the article, and the {{em|converted}} unit to be shown as primary: <code><nowiki>{{convert|200|mi|km|order=flip}}</nowiki></code> &rarr; {{xt|The two cities are {{convert|200|mi|km|order=flip}} apart.}}

===Unit conversions===

{{see also|#Currency conversions|Misplaced Pages:WikiProject Astronomy/Manual of Style#Units}}
{{shortcut|MOS:CONVERSIONS|MOS:CVT}}

Where English-speaking countries use different units for the same quantity, provide a conversion in parentheses: {{xt|the Mississippi River is {{convert|2320|mi|km|0}} long}}; {{xt|the Murray River is {{convert|2508|km|mi|0}} long}}. But in science-related articles, supplying such conversion is not required unless there is some special reason to do so.
* Where an ] is not part of the ], or vice versa{{snd}}and in particular, where those systems give a single term different definitions{{snd}}a double conversion may be appropriate: {{xt|Rosie weighed {{convert|80|kg|lb stlb}}}} (markup: <code><nowiki>{{convert|80|kg|lb stlb}}</nowiki></code>); {{xt|{{nobr|The car}} had a fuel economy of {{convert|5|L/100km|mpgus mpgimp|abbr=on}}}} (markup: <code><nowiki>{{convert|5|L/100km|mpgus mpgimp|abbr=on}}</nowiki></code>).
* Generally, conversions to and from metric units and US or imperial units should be provided, except:
** When inserting a conversion would make a common or linked expression awkward ({{xt|The four-minute mile}}).
** In some topic areas (for example, maritime subjects where nautical miles are the primary units, American football where ] are primary, and articles like ] where many interplanetary distances are given) it can be excessive to provide a conversion for every quantity. In such cases consider noting that the article will use a particular unit{{snd}}possibly giving the conversion factor to other, familiar units in a parenthetical note or a footnote{{snd}}and link the first occurrence of each unit but not give a conversion every time it occurs. Applying this principle may require editorial discretion; for example, in scientific articles the expected level of reader sophistication should be taken into account. <!-- At http://en.wikipedia.org/Wikipedia_talk:Manual_of_Style/Dates_and_numbers/Archive_155#Unit_conversions_in_science_articles there's a very long and detailed discussion about this point which kind of pooped out and might be worth reviving-->
** For distances on the scale of between ]s and ], "]s" or "ly" should be used as primary units, with a conversion to "parsecs" or "pc", but no conversion to SI units. The units should be linked on first mention. For larger quantities, use ] in prose (million or billion but not thousand) and metric prefixes (kly, Mly, Gly, kpc, Mpc, Gpc) in compact contexts. Examples:<!-- -->
*** First mention in prose: {{convert|34.6|±|2.3|e6ly|Mpc|sigfig=3|lk=on}}
**** Wikitext: <nowiki>{{convert|34.6|±|2.3|e6ly|Mpc|sigfig=3|lk=on}}</nowiki>
*** Infobox or table: {{cvt|765|kpc|Mly|order=flip|sigfig=3|lk=on}}
**** Wikitext: <nowiki>{{cvt|765|kpc|Mly|order=flip|sigfig=3|lk=on}}</nowiki> (use "order=flip" when source uses parsecs)
** ]s (au) should be converted to kilometers (km) using "million", "billion", or "trillion" in both prose and compact environments like infoboxes and tables. When large interplanetary-scale distances overlap with small interstellar-scale distances, convert au to ly and pc, or ly to pc and au (depending on context). Examples: <!-- ] -->
*** {{convert|49.3|au|e9km|abbr=unit}}
**** Wikitext: <nowiki>{{convert|49.3|au|e9km|abbr=unit}}</nowiki>
*** {{convert|121000|au|ly pc|abbr=off|lk=on}}
**** Wikitext: <nowiki>{{convert|121000|au|ly pc|abbr=off|lk=on}}</nowiki>
*** {{convert|0.9|ly|pc au|abbr=unit}}
**** Wikitext: <nowiki>{{convert|0.9|ly|pc au|abbr=unit}}</nowiki>

* For units of measure that are obsolete, obscure outside of a particular specialty or geography (e.g. ], ], or ]), or not part of the SI/] or US customary systems (e.g. zolotnik), supply a parenthetical conversion into at least SI or SI-accepted units (unless one of the exceptions previously noted applies). Convert each mention, unless this would be excessive given the context. Take care to distinguish between different definitions of the same unit if it has changed over time or differs geographically (e.g. ], ]). An approximate or range conversion is acceptable if the exact historical value is uncertain (e.g. ]).
** Metric units not part of the SI or accepted for use with it should either be replaced with SI or SI-accepted units (e.g. joules instead of ]s), or they should be treated as obscure units in the same way as furlongs.
* ]es used should be commonly known, namely "pico" thru "tera", preferably in commonly-used combinations (e.g. 2,000 kilometers not 2 megameters).
* Converted quantity values should use a {{em|level of precision}} similar to that of the source quantity value, so {{xt|the Moon is 380,000{{nbsp}}kilometres (240,000{{nbsp}}mi) from Earth}}, not {{!xt|(236,121{{nbsp}}mi)}}. Small numbers, especially if approximate, may need to be converted to a range where rounding would cause a significant distortion, so {{xt|about one mile (1–2{{nbsp}}km)}}, not {{!xt|about one mile (2{{nbsp}}km)}}. Be careful especially when your source has already converted from the units you're now converting back to. This may be evidenced by multiples of common conversion factors in the data, such as 160 km (from 100 miles). {{crossref|See ].}}
* {{tlx|convert}} and other ] can be used to convert and format many common units, and have options to respect significant figures. To avoid problems with rounding and significant figures, for input to conversion templates use only the original quantity found in reliable sources, not one that a source has already converted. If required by the above rules, the conversion output can be displayed as the primary units with "order=flip". Conversion output can be displayed as the only units with "disp=out"; this retains the original quantity in wikitext for verification by editors.
* In a '''direct quotation''', always retain the source units. Any conversions can be supplied either in the quote itself (in square brackets, following the original measurement) or in a footnote. {{crossref|See ] and ].}}
* {{tlx|Units attention}} may be added to articles needing general attention regarding choice of units and unit conversions.


===Unit names and symbols=== ===Unit names and symbols===
{{redirect|WP:DEGREE|the essay on notability|WP:POSITION}}
: ''Definitions:''
{{shortcut|MOS:UNITNAMES|MOS:UNITSYMBOLS}}
:* Examples of '''unit names''': foot, meter, kilometer.
:{{em|Definitions:}}
:* Examples of '''unit names''': foot, metre, kilometre, (''US:'' meter, kilometer).
:* Examples of '''unit symbols''': ft, m, km. :* Examples of '''unit symbols''': ft, m, km.

* Unit names and symbols should follow the practice of reliable sources. * Unit names and symbols should follow the practice of reliable sources.
* In prose, unit names should be given in full if used only a few times, but symbols may be used when a unit (especially one with a long name) is used repeatedly, after spelling out the first use (e.g. {{xt|Up to 15{{nbsp}}kilograms of filler is used for a batch of 250{{nbsp}}kg}}). * In prose, unit names should be given in full if used only a few times, but symbols may be used when a unit (especially one with a long name) is used repeatedly, after spelling out the first use (e.g. {{xt|Up to 15 kilograms of filler is used for a batch of 250{{nbsp}}kg}}).
:* Certain unit names (e.g. {{xt|&deg;C}})<!--<<perhaps identify these in table of specific units elsewhere on this page--> need never be written in full unless required stylistically ({{xt|automatic conversion of degrees Celsius to degrees Fahrenheit}}). ** Exception: Certain units<!--<<perhaps identify these in table of specific units elsewhere on this page--> are generally represented by their symbols (e.g. {{xt|&deg;C}} rather than {{!xt|degrees Celsius}}) even on first use, though their unit names may be used for emphasis or clarity ({{xt|conversion of degrees Celsius to degrees Fahrenheit}}).
** Exception: Consider using ''inches'' (but not ''in.'') in place of ''in'' where the latter might be misread as a preposition<!--can someone supply an example? (if no one can think of one after a while, then maybe this exception never actually arises)-->{{mdashb}}but not where the value is followed by a parenthesized conversion e.g. {{xt|bolts 5{{nbsp}}in (12.7{{nbsp}}cm) long}}, or is part of such a conversion ({{xt|bolts 12.7{{nbsp}}cm (5{{nbsp}}in) long}}).
* Where space is limited, such as in tables, infoboxes, parenthetical notes, and mathematical formulas, unit symbols are preferred. * Where space is limited, such as in tables, infoboxes, parenthetical notes, and mathematical formulas, unit symbols are preferred.
* Units unfamiliar to general readers should be presented as a name{{ndash}}symbol pair on first use, linking the unit name ({{xt|Energies were originally 2.3{{nbsp}}]s (MeV), but were eventually 6{{nbsp}}MeV}}). * Units unfamiliar to general readers should be presented as a name{{ndash}}symbol pair on first use, linking the unit name ({{xt|Energies rose from 2.3 ]s (MeV) to 6{{nbsp}}MeV}}).
** Commonly-known SI and SI-accepted units that can be used without linking are: meter (m), gram (g), second (s), ampere (A), liter (L), pascal (Pa), hertz (Hz), degrees Celsius (°C), minute (min), hour (h), day (d), degree (of angle, °), volt (V), watt (W)
* Ranges use unspaced en dash ({{tlx|ndash}}) if only one unit symbol is used at the end (e.g. {{xt|5.9{{ndash}}6.3{{nbsp}}kg}}), and spaced en dash ({{tlx|snd}}) if two symbols are used (e.g. {{xt|3{{nbsp}}μm{{snd}}1{{nbsp}}mm}}); ranges in prose may be specified using either unit symbol ''or'' unit names, and units may be stated either after both numerical values or after the last (e.g. {{xt|from 5.9 to 6.3{{nbsp}}kilograms}}, {{xt|from 5.9{{nbsp}}kilograms to 6.3{{nbsp}}kilograms}}, {{xt|from 5.9 to 6.3{{nbsp}}kg}} and {{xt|from 5.9{{nbsp}}kg to 6.3{{nbsp}}kg}} are all acceptable).
* Ranges use unspaced en dash ({{tlx|ndash}}) if only one unit symbol is used at the end (e.g. {{xt|5.9{{ndash}}6.3{{nbsp}}kg}}), and spaced en dash ({{tlx|snd}}) if two symbols are used (e.g. {{xt|3{{nbsp}}μm{{snd}}1{{nbsp}}mm}}); ranges in prose may be specified using either unit symbol or unit names, and units may be stated either after both numerical values or after the last (all acceptable: {{nobr|{{xt|from 5.9 to 6.3 kilograms}}}}; {{nobr|{{xt|from 5.9 kilograms to 6.3 kilograms}}}}; {{nobr|{{xt|from 5.9 to 6.3{{nbsp}}kg}}}}; {{nobr|{{xt|from 5.9{{nbsp}}kg to 6.3{{nbsp}}kg}}}}).
* Length{{ndash}}width, length{{ndash}}width{{ndash}}height and similar dimensions may be separated by the multiplication sign ({{xt|]}}) or the word ''by''.
* Length{{ndash}}width, length{{ndash}}width{{ndash}}height and similar dimensions may be separated by the multiplication sign (<code>×</code> or <code>&amp;times;</code>) or the word <code>by</code>.
** With the multiplication sign, each number should be followed by a unit name or symbol (if appropriate):
** The {{xtn|×}} symbol is preceded by a space (preferably non-breaking), and followed by a space (which may also be non-breaking in short constructions), and each number should be followed by a unit name or symbol:
:: &nbsp; &bull; &nbsp;{{xt|1{{nbsp}}m &times; 3{{nbsp}}m &times; 6{{nbsp}}m}}, not {{nobr| {{!xt|1 &times; 3 &times; 6 m}} }}, {{!xt|(1 &times; 3 &times; 6){{nbsp}}m}} nor {{nobr| {{!xt|1 &times; 3 &times; 6{{nbsp}}m<sup>3</sup>}} }}
*** {{xt|1 m × 3 m × 6 m}}, not {{nobr| {{!xt|1 × 3 × 6 m}}}}, {{!xt|(1 × 3 × 6) m}}, nor {{nobr| {{!xt|1 × 3 × 6 m<sup>3</sup>}} }}
:: &nbsp; &bull; &nbsp;{{xt|a metal plate 1{{nbsp}}ft &times; 3{{nbsp}}ft &times; 0.25{{nbsp}}in}}
*** {{xt|a metal plate 1 ft × 3 ft × 0.25 in}}
:: &nbsp; &bull; &nbsp;{{xt|a railroad ] 10{{nbsp}}ft &times; 2.5{{nbsp}}mi}}
*** {{xt|a railroad easement 10 ft × 2.5 mi}}
:* With ''by'' the unit need be given only once: {{nobr| {{xt|1 by 3 by 6 metres}} }} or {{nobr| {{xt|1 by 3 by 6 m}} }}
** With ''{{xtn|by}}'', the unit need be given only once if it is the same for all dimensions: {{nobr| {{xt|1 by 3 by 6 metres}} }} or {{nobr| {{xt|1 by 3 by 6 m}}}}.
:* The unspaced letter {{xt|x}} may be used in common terms such as {{xt|]}}.
** The unspaced letter {{xt|x}} may be used in common terms such as {{xt|]}}.


{| class="wikitable" {| class="wikitable"
|+ General guidelines on unit names and symbols |+ {{vanchor|General guidelines on use of units}}
|- |-
! Aspect ! {{Vert header|<small>Aspect</small>}}
! Guideline<!--this column picks up whatever width is left over from other columns-->
! width="500px"|Guideline
! ] Acceptable ! style="width:40px;"<!--undersized width specification means column size is set by widest word/nobreaked phrase in column contents-->| ] Acceptable
! ] Unacceptable ! style="width:40px;"<!--undersized width specification means column size is set by widest word/nobreaked phrase in column contents-->|] Unacceptable
|- |-
|rowspan=8 {{Vert header|va=middle|<small>'''Unit names and symbols'''</small>}}
|'''Spelling'''
|Except as listed in the {{section link||Specific units}} table below, unit {{em|symbols}} are uncapi{{shy}}tal{{shy}}ized unless they are derived from a proper name, in which case the first letter (of the base unit symbol, not of any prefix) is capitalized.{{efn|1=These definitions are consistent with all units of measure mentioned in the ''SI Brochure''<ref name="SI Brochure" /> and with all units of measure catalogued in ].<ref>{{cite web |title=Council Directive of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement |id=80/181/EEC (Document 01980L0181-20090527) |work=Eur-Lex.Europa.eu |publisher=] |date=2017 |orig-year=1979 |url=http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1397640809938&uri=CELEX:01980L0181-20090527 |access-date=December 12, 2017}}</ref>}}
|The spelling of certain unit names (some of which are listed in {{section link||Specific units}}, below) varies with the ].
| {{ xt|8 kg}}<br>{{ xt|100 kPa}}
|
| {{!xt|8 Kg}}<br>{{!xt|100 kpa}}
|
|- |-
|Unit symbols are undotted.
|rowspan=13|'''Format'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - -->
|{{ xt|38 cm of rope }}
|Do not spell out numbers before unit ''symbols''{{nbsp}}...
|{{ xt|5{{nbsp}}min}} |{{!xt|38 cm<big>.</big> of rope}}
|{{!xt|five{{nbsp}}min}}
|- |-
|rowspan=2 | Unit {{em|names}} are given in lower case except: where any word would be capital{{shy}}ized, or where otherwise specified in the SI brochure<ref name="SI Brochure">{{cite book |title=SI Brochure: The International System of Units (SI) |edition=9th |year=2019 |publisher=] |url=https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochure-9-EN.pdf |section=Chapter 4: Non-SI units that are accepted for use with the SI |access-date=2020-09-24}} Table 8, p 145, gives additional guidance on non-SI units.</ref> or this Manual of Style.
|...{{nbsp}}but words <u>or</u> numerals may be used with unit ''names''.
|{{plainlist| |{{plainlist|
* {{ xt|five minutes}} * {{ xt|A gallon is 4{{nbsp}}quarts.}}
* {{ xt|5 minutes}} * {{ xt|4 pascals}}
}}
|{{plainlist|
* {{!xt|A Gallon is 4{{nbsp}}Quarts.}}
* {{!xt|4 Pascals}}
}}
|-
|{{plainlist|
* {{ xt|He walked several miles.}}
* {{ xt|Miles of trenches were dug.}}
}} }}
| |
|- |-
|The spelling of certain unit names (some of which are listed in {{section link||Specific units}}, below) varies with the ].
| Values not accompanied by units are usually given in figures.<!--doing my best to make sense of this -- help gratefully accepted -->
|
| {{ xt|Set the control to 10.}}
|
| {{!xt|Set the control to ten.}}
|- |-
|rowspan=3 | Write unit names and symbols in upright roman type, except where italics are used for emphasis. |rowspan=2 | Write unit names and symbols in upright (]) type, except where emphasizing in context.
| {{ xt|10{{nbsp}}m}} | {{ xt|10{{nbsp}}m}}<br>{{ xt|29 kilograms}}
| {{!xt|10{{nbsp}}''m''}} | {{!xt|10{{nbsp}}{{em|m}}}}<br>{{!xt|29 {{em|kilograms}}}}
|- |-
| {{ xt|Thus each two-liter jug contained only two {{em|quarts}}.}}
| {{ xt|29{{nbsp}}kilograms}}
|
| {{!xt|29{{nbsp}}''kilograms''}}
|- |-
|Do not use precomposed unit symbol characters.
| {{ xt|Therefore, each two-liter jug contained only two ''quarts''.}}
| |
|{{!xt|㎓, ㎦, ㎍, ㎖, ㎉}}
|- |-
|rowspan=7 {{Vert header|va=middle|<small>'''Numeric values'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|Unit ''names'' are given in lower case except: in places where any word would be capital{{shy}}ized; where otherwise specified in the SI brochure; where otherwise specified in this Manual of Style.{{clarify}}
|Do not spell out numbers before unit {{em|symbols}}{{nbsp}}...
|{{ xt|12{{nbsp}}min}}
|{{!xt|twelve{{nbsp}}min}}
|-
|...{{nbsp}}but words {{em|or}} figures may be used with unit {{em|names}}.
|{{plainlist| |{{plainlist|
* {{ xt|He walked several miles.}} * {{ xt|twelve minutes}}
* {{ xt|Miles of trenches were dug.}} * {{ xt|12 minutes}}
}} }}
|
|{{!xt|A Gallon equals 4 Quarts.}}
|- |-
| Use a non-breaking space ({{tlx|nbsp}} or <code>&amp;nbsp;</code>) between a number and a unit {{em|symbol}}, or use {{tlx|nowrap}}{{nbsp}}...
|rowspan=2 | Except as listed in the "Specific units" table below, unit ''symbols'' are uncapi{{shy}}tal{{shy}}ized unless they are derived from a proper name, in which case the first letter (of the base unit symbol, not of any prefix) is capitalized.<ref>This definition is consistent with all units of measure mentioned in the 8th edition of the ] and with all units of measure catalogued in ]</ref>
| {{xt|29{{nbsp}}kg}} {{nowr|(markup: <code>29&amp;nbsp;kg</code>}} or {{nowr|<code><nowiki>{{nowrap|29 kg}}</nowiki></code>)}}
| {{ xt|8 kg }}
| {{!xt|8 Kg }} | style="vertical-align: top"| {{!xt|29kg}}
|- |-
| ... though with certain symbols ''no'' space is used (see "Specific{{nbsp}}units" table below){{nbsp}}...
| {{ xt|100 kPa}}
| {{nobr|{{xt|23&deg;}} {{xt|47&prime;}} {{xt|22&Prime;}} }}
| {{!xt|100 kpa}}
| {{nobr|{{!xt|23{{nbsp}}&deg;}} {{!xt|47{{nbsp}}&prime;}} {{!xt|22{{nbsp}}&Prime;}} }}
|- |-
| ... and a normal space is used between a number and a unit {{em|name}}.
|Unit symbols are undotted.
| {{xt|29{{nbsp}}kilograms}}<br>(markup: <code>29{{nbsp}}kilograms</code>)
|{{ xt|38 cm }}
|
|{{!xt|38 cm.}}
|-
|Except as shown in the "Specific units" table below, a space appears between a numeric value and a unit name or symbol. In the case of unit ''symbols'',<!--<<restriction of nowrap markup to symbols, not full unit names, seems to be implied by earlier text in this guideline--> <code><nowiki>&amp;nbsp;</nowiki></code> (or {{tlx|nowrap}}{{px1}}) should be used to prevent linebreak.''
|{{ xt|29{{nbsp}}kg}}<br />''Markup:'' <code>29&amp;nbsp;kg</code><!--<<add examples of degree etc-->
|{{!xt|29kg}}
|- |-
|To form a value and a unit ''name'' into a compound adjective use a hyphen or hyphens{{nbsp}}... |To form a value and a unit {{em|name}} into a compound adjective use a hyphen or hyphens{{nbsp}}...
|{{plainlist| |{{plainlist|
* {{ xt|a five-day holiday }} * {{ xt|a five-day holiday}}
* {{ xt|a five-cubic-foot box}} * {{ xt|a five-cubic-foot box}}
* {{ xt|a 10-centimeter blade}} * {{ xt|a 10-centimeter blade}}
Line 553: Line 758:
| |
|- |-
|... but a non-breaking space (never hyphen) separates a value and unit ''symbol''. |... but a non-breaking space (never hyphen) separates a value and unit {{em|symbol}}.
|{{plainlist| |{{plainlist|
* {{ xt|a blade 10 cm long }}<!-- what about "a 10 cm bridge" OK?--> * {{ xt|a blade 10 cm long}}<!--What about "a 10 cm bridge"?-->
}} }}
| {{!xt|a 10-cm blade}} | {{!xt|a 10-cm blade}}
|- |-
|rowspan=8| '''Plurals'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - --> |rowspan=5 {{Vert header|va=middle|<small>'''Plurals'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|SI unit ''names'' are pluralized by adding ''s'' or ''es''...<!--not that it matters much, but I'm having trouble finding an SI unit taking -es --> |] unit {{em|names}} are pluralized by adding {{xt|-s}} or {{xt|-es}}{{nbsp}}...<!--Not that it matters much, but I'm having trouble finding an SI unit taking -es. -->
|{{ xt|1 ohm}}, {{xt|10 ohms}}<!--what's an example with "es"?--> |{{ xt|1 ohm}}; {{xt|10 ohms}}<!--What's an example with "-es"?-->
| |
|- |-
|rowspan=4 | ... except for these irregular forms. | ... except for these irregular forms.
| {{ xt|1 henry}}, {{ xt|10 henries}} | {{ xt|1 henry}}; {{ xt|10 henries}}<br>{{ xt|1 hertz}}; {{ xt|10 hertz}}<br>{{ xt|1 lux}}; {{xt|10 lux}}<br>{{ xt|1 siemens}}; {{xt|10 siemens}}
| {{!xt|10 henrys }} |{{!xt|10 henrys }}<br>{{!xt|10 hertzes}}<br>{{!xt|10 luxes}}<br>{{!xt|10 siemenses}}
|- |-
|rowspan=2 | Some non-SI units have irregular plurals.<!--This is meant to be placeholder which perhaps someone can expand (though foot, feet is the only example I can think of at the moment).--><!--Pedal, peddle (more, meet; group, greet; trump, tweet) ... mouth, momentous ... are we there yet ...-->
| {{ xt|1 hertz}}, {{ xt|10 hertz }}
| {{!xt|10 hertzes}} | {{ xt|1 foot}}; {{xt|10 feet}}
|-
| {{ xt|1 lux}}, {{ xt|10 lux }}
| {{!xt|10 luxes }}
|-
| {{ xt|1 siemens}}, {{ xt|10 siemens}}
|
|-
|rowspan=2 | Some non-SI units have irregular plurals.<!--this is meant to be placeholder which perhaps someone can expand (though foot, feet is the only example I can think of at the moment)-->
| {{ xt|1 foot}}, {{ xt|10 feet}}
| {{!xt|10 foots}} | {{!xt|10 foots}}
|- |-
| {{ xt|1 stratum}}, {{ xt|10 strata}} (unusual) <!-- rare, but is occasionally used as a measurement unit; can't think of any others, didn't find any in searching --> | {{ xt|1 stratum}}; {{nobr|{{xt|10 strata}} (unusual)}} <!--Rare, but is occasionally used as a measurement unit; can't think of any others, didn't find any in searching.-->
| {{!xt|10 stratums}} | {{!xt|10 stratums}}
|- |-
|Unit ''symbols'' (in any system) are identical in singular and plural. |Unit {{em|symbols}} (in any system) are identical in singular and plural.
|{{plainlist| |{{plainlist|
* {{nobr|{{ xt|grew from 1 in to 2 in }} }} * {{nobr|{{xt|grew from 1 in to 2 in}} }}
* {{nobr|{{ xt|grew from 1 inch to 2 inches}} }} * {{nobr|{{xt|grew from 1 inch to 2 inches}} }}
* {{nobr|{{ xt|grew from one to two inches }} }} * {{nobr|{{xt|grew from one to two inches}} }}
}} }}
|{{nobr|{{!xt|grew from 1 in to 2 ins }} }} |{{nobr|{{!xt|grew from 1 in to 2 ins}} }}
|- |-
|rowspan=6|'''Powers'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - --> |rowspan=5 {{Vert header|va=middle|<small>'''Powers'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|Format exponents using <code><nowiki><sup></nowiki></code>, not special characters. |Format exponents using <nowiki><sup></nowiki>, not special characters.
|{{ xt|km<sup>2</sup>}}<br />''Markup:'' <code>km&lt;sup>2&lt;/sup></code> |{{xt|km<sup>2</sup>}}<br>{{nobr|(markup: <code>km&lt;sup>2&lt;/sup></code>)}}
|''Markup (deprecated):'' <s><code>km&amp;#178;</code></s> |{{!xt|km&#178;}}<br>(<code>km&amp;#178;</code>)
|- |-
|Or use ''squared'' or ''cubed'' (''after'' the unit being modified). |Or use {{xtn|squared}} or {{xtn|cubed}} ({{em|after}} the unit being modified).
|rowspan=2|{{ xt|ten metres per second squared}} |rowspan=2|{{xt|ten metres per second squared}}
|{{!xt|ten metres per squared second}} |{{!xt|ten metres per squared second}}
|- |-
|rowspan=2| For areas or volumes only, ''square'' or ''cubic'' may be used (''before'' the unit being modified). |rowspan=2| For areas or volumes only, {{xtn|square}} or {{xtn|cubic}} may be used ({{em|before}} the unit being modified).
|{{!xt|ten metres per square second}} |{{!xt|ten metres per square second}}
|- |-
|{{ xt|tons per square mile}} |{{xt|tons per square mile}}
| |
|- |-
|rowspan=2| ''sq'' or ''cu'' may be used with US customary or imperial units, but not with SI units. | {{xtn|sq}} or {{xtn|cu}} may be used with US customary or imperial units, but not with ] units.
| {{ xt|15{{nbsp}}sq{{nbsp}}mi}} | {{ xt|15{{nbsp}}sq{{nbsp}}mi}}<br>{{ xt|3{{nbsp}}cu{{nbsp}}ft }}
| {{!xt|15{{nbsp}}sq{{nbsp}}km}} | {{!xt|15{{nbsp}}sq{{nbsp}}km}}<br>{{!xt|3{{nbsp}}cu{{nbsp}}m }}
|-
| {{ xt|3{{nbsp}}cu{{nbsp}}ft }}
| {{!xt|3{{nbsp}}cu{{nbsp}}m }}
|- |-
|rowspan=4|'''Products'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - --> |rowspan=4 {{Vert header|va=middle|<small>'''Products'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|Indicate a product of unit ''names'' with either a hyphen or a space. |Indicate a product of unit {{em|names}} with either a hyphen or a space.
|{{plainlist| |{{plainlist|
* {{ xt|foot-pound}} * {{ xt|foot-pound}}
Line 621: Line 814:
}} }}
|{{plainlist| |{{plainlist|
* {{!xt|footpound }} * {{!xt|footpound}}
* {{!xt|foot&middot;pound}} * {{!xt|foot&sdot;pound}}
}} }}
|- |-
|Indicate a product of unit ''symbols'' with <code>&amp;];</code> or <code>&amp;];</code> (''Note:'' {{tlx|middot}} is not equivalent to <code>&amp;middot;</code>.) |Indicate a product of unit {{em|symbols}} with <code>&amp;];</code> or <code>&amp;];</code>.
|{{plainlist|1= <!-- 1= is needed because text below contains = --> |{{plainlist|1= <!-- 1= is needed because text below contains = -->
* {{ xt|ms }} = millisecond * {{ xt|ms}} = millisecond
* {{ xt|m&middot;s}} or {{xt|m{{nbsp}}s}} = metre-second * {{ xt|m&sdot;s}} or {{xt|m{{nbsp}}s}} = metre-second
}} }}
| |
|- |-
|''Exception:'' In some topic areas such as power engineer{{shy}}ing, certain products take neither space nor <code>&amp;middot;</code>. Follow the practice of reliable sources in the article's topic area. |{{em|Exception:}} In some topic areas, such as power engineer{{shy}}ing, certain products take neither space nor <code>&amp;sdot;</code>. Follow the practice of reliable sources in the article's topic area.
|{{plainlist| |{{plainlist|
* ], ], ] * ], ], ]
Line 639: Line 832:
| |
|- |-
|To pluralize a product of unit ''names'', pluralize only the final unit. (Unit ''symbols'' are never pluralized.) |To pluralize a product of unit {{em|names}}, pluralize only the final unit. (Unit {{em|symbols}} are never pluralized.)
|{{ xt|ten foot-pounds }} |{{ xt|ten foot-pounds}}
|{{!xt|ten feet-pounds }} |{{!xt|ten feet-pounds}}
|- |-
|rowspan=7|'''Ratios,<br />Rates,<br />Densities'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - --> |rowspan=7 {{Vert header|va=middle|<small>'''Ratios, rates, densities'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|Indicate a ratio of unit ''names'' with ''per''. |Indicate a ratio of unit {{em|names}} with {{xtn|per}}.
|{{ xt|meter per second}} |{{ xt|meter per second}}
|{{!xt|meter/second}} |{{!xt|meter/second}}
|- |-
|rowspan=2|Indicate a ratio of unit ''symbols'' with a slash (followed by either a single symbol or a parenthesized product of symbols{{mdashb}}do not use multiple slashes); or use{{nbsp}}<sup>&minus;1</sup>,{{nbsp}}<sup>&minus;2</sup>, etc. |rowspan=2|Indicate a ratio of unit {{em|symbols}} with a forward slash (<code>/</code>), followed by either a single symbol or a parenthesized product of symbols{{snd}}do not use multiple slashes. Or use{{nbsp}}<sup>&minus;1</sup>,{{nbsp}}<sup>&minus;2</sup>, etc.
|{{plainlist| |{{plainlist|
* {{ xt|metre per second }} * {{ xt|metre per second}}
* {{ xt|m/s }} * {{ xt|m/s}}
* {{ xt|m&middot;s<sup>&minus;1</sup>}} * {{ xt|m&sdot;s<sup>&minus;1</sup>}}
}} }}
|{{plainlist| |{{plainlist|
Line 659: Line 852:
|- |-
|{{plainlist| |{{plainlist|
* {{ xt|kg/(m&middot;s) }} * {{ xt|kg/(m&sdot;s)}}
* {{ xt|kg&middot;m<sup>&minus;1</sup>&middot;s<sup>&minus;1</sup>}} * {{ xt|kg&sdot;m<sup>&minus;1</sup>&sdot;s<sup>&minus;1</sup>}}
}} }}
|{{plainlist| |{{plainlist|
* {{!xt|kg/m&middot;s}} * {{!xt|kg/m&sdot;s}}
* {{!xt|kg/m/s }} * {{!xt|kg/m/s}}
}} }}
|- |-
|To pluralize a ratio of unit ''names'', pluralize only the "numerator" unit. (Unit ''symbols'' are never pluralized.) |To pluralize a ratio of unit {{em|names}}, pluralize only the numerator unit. (Unit {{em|symbols}} are never pluralized.)
|{{plainlist| |{{plainlist|
* {{nowrap|{{ xt|ten newton-metres per second}} }}<!--nowrap on longest value in column establishes minimum col width--> * {{nowrap|{{xt|ten newton-metres per second}} }}<!--Nowrap on longest value in column establishes minimum col width.-->
* {{ xt|10 N&middot;m/s }} * {{xt|10 N&sdot;m/s}}
}} }}
| |
|- |-
|Some of the special forms used in the imperial and US customary systems are shown here{{nbsp}}... |Some of the special forms used in the imperial and US customary systems are shown here{{nbsp}}...
|{{plainlist|1= <!-- 1= is needed because text below contains = --> |{{plainlist|1= <!--1= is needed because text below contains =-->
* {{ xt|mph}} = miles per hour * {{ xt|mph}} = miles per hour
* {{ xt|mpg}} = miles per gallon * {{ xt|mpg}} = miles per gallon
* {{ xt|psi}} = ]s per square inch * {{ xt|psi}} = ] per square inch
}} }}
| |
Line 684: Line 877:
|rowspan=2| ... but only the slash or negative exponent notations are used with SI (and other metric) units. |rowspan=2| ... but only the slash or negative exponent notations are used with SI (and other metric) units.
| {{plainlist| | {{plainlist|
* {{ xt|g/m<sup>2</sup> }} * {{ xt|g/m<sup>2</sup>}}
* {{ xt|g&middot;m<sup>&minus;2</sup>}} * {{ xt|g&sdot;m<sup>&minus;2</sup>}}
}} }}
| {{!xt|gsm}} | {{!xt|gsm}}
|- |-
| {{plainlist| | {{plainlist|
* {{ xt|km/h }} * {{ xt|km/h}}
* {{ xt|km&middot;h<sup>&minus;1</sup>}} * {{ xt|km&sdot;h<sup>&minus;1</sup>}}
}} }}
| {{!xt|kph}} | {{!xt|kph}}
|- |-
|rowspan=8|'''Prefixes'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - --> |rowspan=4 {{Vert header|va=middle|<small>'''Prefixes'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
|Prefixes should not be separated by a space or hyphen. |Prefixes should not be separated by a space or hyphen.
|{{ xt|25 kilopascals}} |{{ xt|kilopascal}}
|{{plainlist| |{{plainlist|
* {{!xt|25 kilo pascals}} * {{!xt|kilo pascal}}
* {{!xt|25 kilo-pascals}} * {{!xt|kilo-pascal}}
}} }}
|- |-
|rowspan=3| Prefixes are added without contraction,<!--give example--> except as shown here: | Prefixes are added without contraction,<!--give example--> except as shown here:
| {{ xt|kilohm }} | {{ xt|kilohm }}<br>{{ xt|megohm }}<br>{{xt|hectare}}
| {{!xt|kiloohm}} | {{!xt|kiloohm}}<br>{{!xt|megaohm}}<br>{{!xt|hectoare}}
|- |-
|The {{xtn|deci-}}, {{xtn|deca-}}, and {{xtn|hecto-}} prefixes should generally be avoided; exceptions include<!--Check SI source; also, since we're supposed to follow the units in sources, don't those control anyway?--> decibel, hectolitre, hectare, and hectopascal.
| {{ xt|megohm }}
| {{!xt|megaohm}}
|-
| {{ xt|hectare}}
| {{!xt|hectoare}}
|-
|''centi-'', ''deci-'', ''deca-'', and ''hecto-'' should be avoided; exceptions include<!--check SI source; also, since we're supposed to follow the units in sources, don't those control anyway?--> ''centimetre, decibel, hectolitre, hectare, hectopascal''.
|{{plainlist| |{{plainlist|
* {{ xt|100 metres}} * {{ xt|100 metres}}
Line 720: Line 907:
|{{!xt|1 hectometre}} |{{!xt|1 hectometre}}
|- |-
|rowspan=3| Do not use ''{{!xt|]}}'' for 10<sup>3</sup>, ''MM'' for 10<sup>6</sup>, or ''B'' for 10<sup>9</sup>.<!-- what about e.g. "deficit of $10B"; MCM = kcmil; etc--> | Do not use ] for 10<sup>3</sup>, {{!xt|MM}} for 10<sup>6</sup>, or {{!xt|B}} for 10<sup>9</sup> (except as noted elsewhere on this page for {{xtn|M}} and {{xtn|B}}, e.g. ])
| {{ xt|3 km }} | {{ xt|3 km }}<br>{{ xt|8 MW }}<br>{{ xt|125 GeV}}
| {{!xt|3 Mm }} | {{!xt|3 Mm }}<br>{{!xt|8 MMW }}<br>{{!xt|125 BeV}}
|- |-
|rowspan=4 {{Vert header|va=middle|<small>'''Mixed units'''</small>}}<!--← Use <br> to make this column as narrow as possible.--><!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES-->
| {{ xt|8 MW }}
|rowspan=2| Mixed units are traditionally used with the imperial and US customary systems{{nbsp}}...
| {{!xt|8 MMW }}
|{{anchor|Mixed units}}<!--← This anchor should go at the portion of the row which is vertically highest.-->{{plainlist|
|-
| {{ xt|125 GeV}} * {{xt|a wall 1 ft 1 in thick}}
| {{!xt|125 BeV}} * {{xt|a wall 1 foot 1 inch thick }}
* {{xt|a man 6 feet 2 inches tall}}
|-
* {{xt|a 6-foot 2-inch man}}
|rowspan=5|'''Mixed<br />units'''<!--<< <br /> to make this column as narrow as possible--><!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF RULES - - - -->
* {{xt|a 6 ft 2 in man}}
|rowspan=2| Mixed units are traditionally used with the imperial and US customary systems{{nbsp}}…
}}
|{{anchor|Mixed units}}<!--<<this anchor should go at the portion of the row which is vertically highest-->{{plainlist|
|{{plainlist|
* {{ xt|1 ft 6 in }}
* {{ xt|1 foot 6 inches}} * {{nobr| {{!xt|1 ft{{hsp}}, 1 in }} (no comma) }}
* {{ xt|1.5 ft }} * {{!xt|1 foot{{hsp}}, 1 inch}}
* {{ xt|18 in }} * {{!xt|a man 6 foot 2 tall}}
* {{!xt|a 6-foot 2 man}}
* {{nbsp}}
}} }}
|
|- |-
|{{plainlist| |{{plainlist|
* {{ xt|1 US fl pt 8 oz}} * {{xt|1 US fl pt 8 oz}}
* {{ xt|1 US fl pt 8 US fl oz}} * {{xt|1 US fl pt 8 US fl oz}}
}} }}
| |
Line 748: Line 936:
|... and in expressing time durations{{nbsp}}... |... and in expressing time durations{{nbsp}}...
|{{plainlist| |{{plainlist|
* {{ xt|1:30:07}} * {{xt|1:30:07}}
* {{ xt|1:30}}{{thinsp}}<ref group=note>Only use this format if it is clear from the context whether this means hours and minutes (H:MM) or minutes and seconds (M:SS).</ref> * {{xt|1:30}}{{thinsp}}<ref group="note">Use this format only where it is clear from context whether it means hours and minutes (HH:MM) or minutes and seconds (MM:SS).</ref>
* {{ xt|{{nobr|1 hr 30 min 7 sec}}}} * {{xt|{{nobr|1 h 30 min 7 s}}}}
* {{xt|{{nobr|01<sup>h</sup> 30<sup>m</sup> 07<sup>s</sup>}}}}{{thinsp}}{{refn|group=note|This format is used in astronomy (see the IAU Style Manual<ref>{{cite book |title=IAU Style Manual |first=G. A. |last=Wilkins |chapter=5.14 Time and angle |page=S23 |date=1989 |url= https://www.iau.org/static/publications/stylemanual1989.pdf |format=PDF |publisher=] |access-date=12 December 2017}}</ref> for details).}}
* {{ xt|{{nobr|1 h 30 m 7 s }}}}
* {{ xt|{{nobr|1<sup>h </sup>30<sup>m </sup>07<sup>s</sup>}}}}
}} }}
||{{plainlist| ||{{plainlist|
* {{!xt|{{nobr|1 h 30 min 7 s }}}}
* {{!xt|{{nobr|1 hr 30 m 7 sec }}}}
* {{!xt|{{nobr|1:30&prime;07&Prime;}}}} * {{!xt|{{nobr|1:30&prime;07&Prime;}}}}
* {{!xt|{{nobr|1:30&prime;}}}}
* {{!xt|{{nobr|1 hr 30 min 7 sec}}}}
* {{!xt|{{nobr|1 h 30 m 7 s}}}}
}} }}
|- |-
| but are not normally used in SI. |... but are not used with metric units.
|{{plainlist| |{{plainlist|
* {{ xt|1.33 m }} * {{xt|1.33 m }}
* {{ xt|133 cm }} * {{xt|133 cm }}
}} }}
|{{!xt|1 m 33 cm}} |{{!xt|1 m 33 cm}}
|-
|No comma.
|{{ xt|6 lb 3 oz}}
|{{!xt|6 lb, 3 oz}}
|} |}
''Note to table:'' {{em|Note to table:}}
{{reflist | group=note}} {{reflist | group=note}}


===Specific units=== ===Specific units===

{{shortcut|MOS:FOOT|MOS:INCH}}
* The following table lists only units that need special attention. * The following table lists only units that need special attention.
* The should be consulted for guidance on use of other SI units. "Chapter 4" tables 6, 7, 8, and 9 give additional guidance on non-SI units. * The ''SI Brochure''<ref name="SI Brochure" /> should be consulted for guidance on use of other SI and non-SI units.


{|class="wikitable" {|class="wikitable"
|+ Guidelines on specific units |+ Guidelines on specific units
|- |-
! width="79px" | Group ! {{Vert header|<small>Group</small>}}
! style="width:40px;"<!--undersized width specification means column size is set by widest word/nobreaked phrase in column contents-->| Unit name
! width="160px" | Name
! style="width:40px;"<!--undersized width specification means column size is set by widest word/nobreaked phrase in column contents-->| Unit symbol
! width="140px" | Symbol
! Comment<!--this column picks up whatever width is left over from other columns-->
! Comment
|- |-
| rowspan = 11 | '''Length'''<br />'''Speed'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - --> | rowspan = 8 {{Vert header|va=middle|<small>'''Length, speed'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| {{plainlist|
| inch
* inch
| {{ xt|in}}
* foot
| rowspan=2|Do not use <code>&amp;prime;</code> ({{!xt|&prime;}}), <code>&amp;Prime;</code> ({{!xt|&Prime;}}), apostrophe/{{zwsp}}single quote ({{!xt|'}}) or double quote ({{!xt|"}})
}}
|-
| {{plainlist|
| foot
| {{ xt|ft}} * {{ xt|in}}
* {{ xt|ft}}
}}
| Do not use <code>&amp;prime;</code>{{nbsp}}({{!xt|&prime;}}), <code>&amp;Prime;</code>{{nbsp}}({{!xt|{{pprime}}}}), apostrophe{{nbsp}}({{!xt|'}}), or quote{{nbsp}}({{!xt|"}}). Exception: in music, ] notation describes organ stops and wind instrument lengths in feet. A prime may be used with an explanation on first use, e.g. {{tq|a ] (16′) organ pedal stop}}; see ].
|- |-
| foot per second | foot per second
| {{ xt|ft/s}} (''not'' {{!xt|fps}}) | {{xt|ft/s}} ({{em|not}} {{!xt|]}})
| |
|- |-
| ] | ]
| {{ xt|h}} ''or'' {{ xt|hh}} | {{xt|h}} or {{xt|hh}}
| Equal to 4 inches; used in measurement of horses. A dot may be followed by additional inches e.g. ''16.2 hh'' indicates 16 hands 2 inches. | Equal to 4 inches; used in measurement of horses. A dot may be followed by additional inches e.g. {{nobr|{{xt|16.2 hh}}}} indicates {{nobr|16 hands 2 inches.}}
|- |-
|{{plainlist|
| knot
* ]
| {{ xt|kn}} (''not'' {{!xt| ]}} ''or'' {{!xt|]}})<!--not sure how to resolve the conflicting coloration desiderata-->
* {{nobr|knot ]}}
|
* {{nobr|knot ]}}
* {{nobr|knot ]}}
* {{nobr|knot ]}}
* {{nobr|knot ]}}
}}
|{{plainlist|
* {{nobr|{{xt|kn}} {{nobr|({{em|not}} {{!xt|]}}, {{!xt|]}}, or {{!xt|]}})}}}}
* {{nobr|{{xt|KIAS}} or {{xt|kn}}}}
* {{xt|KCAS}}
* {{xt|KEAS}}
* {{xt|KTAS}}
* {{nobr|{{xt|kn}} {{nobr|({{em|not}} {{!xt|KGS}})}}}}
}}
| Used in aviation contexts for aircraft and wind speeds, and also used in some nautical and general meteorological contexts. When applied to aircraft speeds, {{xt|kn}} means {{xt|KIAS}} unless stated otherwise; if {{xt|kn}} is used for calibrated airspeed, equivalent airspeed, true airspeed, or groundspeed, explicitly state and link to, upon first use, the type of speed being referred to (for instance, {{xt|kn ]}}, or, if severely short of space, {{xt|kn ]}}); for airspeeds other than indicated airspeed, the use of the specific abbreviation for the type of airspeed being referred to (such as {{xt|KEAS}}) is preferred. When referring to indicated airspeed, either {{xt|kn}} or {{xt|KIAS}} is permissible. Groundspeeds and wind speeds ''must'' use the abbreviation {{xt|kn}} only.
|- |-
| {{plainlist| | {{plainlist|
* metre * metre
* meter ''(U.S.)'' * meter {{em|(US)}}
}} }}
| {{ xt|m}} | {{xt|m}}
| |
|- |-
| micron | micron
| {{ xt|&mu;m}} (''not'' {{!xt|&mu;}}) | {{xt|&mu;m}} ({{em|not}} {{!xt|&mu;}})
| ''Markup:'' <code>&amp;mu;m</code>{{nbsp}} Link to ] (for which micron is a synonym) on first use. | Markup: <code>&amp;mu;m</code>{{nbsp}} Link to ] (for which micron is a synonym) on first use.
|- |-
| ] | ]
| {{ xt|AU}} (''not'' {{nobr | {{!xt|A.U., au, ua}}) }} | {{xt|au}}<br>{{nobr| ({{em|not}} {{!xt|A.U.}}, {{!xt|ua}}) }}
| The preferred form is {{xt|au}}. Articles that already use {{xtn|AU}} may switch to au or continue with AU; seek consensus on the talk page.
| <ref>"AU" is the most commonly used unit symbol for the astronomical unit, both in popular and professional astronomical articles, and is hence also used on Misplaced Pages. The ] and ] officially recommend "au". See:
*{{cite web |title=Resolution B2 on the re-definition of the astronomical unit of length |url=http://www.iau.org/static/resolutions/IAU2012_English.pdf#page=3 |page=1 |year=2012 |website=International Astronomical Union}}
*{{cite book |author=] |section=Non-SI units accepted for use with the SI, and units based on fundamental constants (contd.) | section-url=http://www.bipm.org/en/publications/si-brochure/table6.html |title=The International System of Units (SI) |url=http://www.bipm.org/en/publications/si-brochure/ |type=Brochure |edition=8th |orig-year=2006 |year=2014}}</ref>
|- |-
|{{plainlist|
| mile
* mile
| {{ xt|mi}}
* miles per hour
|rowspan=3 | In nautical and aeronautical contexts use {{xt|statute mile}}<!--<<should this be an entry in the table?--> rather than mile to avoid confusion with nautical mile.
* nautical mile
|-
}}
| mile per hour
|{{plainlist|
| {{ xt|mph}}<!-- not ever mi/hr??-->
* {{xt|mi}}
|-
* {{xt|mph}}<!--not ever mi/h??-->
| nautical mile
| {{ xt|nmi}} ''or'' {{xt|NM}} {{nobr|(''not'' {{!xt|]}})}} * {{nobr| {{xt|nmi}} or {{xt|NM}} {{nobr|({{em|not}} {{!xt|]}} or {{!xt|M}})}} }}
}}
| In nautical and aeronautical contexts where there is risk of confusion with nautical miles, consider writing out references to ]s as e.g. {{xt|5{{nbsp}}statute{{nbsp}}miles}} rather than simply {{!xt|5{{nbsp}}miles}}.
|- |-
| rowspan = 13 | '''Volume'''<br />'''Flow'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - --> | rowspan = 7 {{Vert header|va=middle|<small>'''Volume, flow'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| rowspan = 2 | {{plainlist| | rowspan = 2 | {{plainlist|
* cubic centimetre * cubic centimetre
* cubic centimeter ''(U.S.)'' * {{nobr| cubic centimeter {{em|(US)}} }}
}} }}
| {{ xt|cm<sup>3</sup>}} | {{xt|cm<sup>3</sup>}}
| ''Markup:'' <code><nowiki>cm<sup>3</sup></nowiki></code> | Markup: <code><nowiki>cm<sup>3</sup></nowiki></code>
|- |-
| {{ xt|cc}} | {{xt|cc}}
| Non-SI symbol used for certain ]s; link to ] on first use.<!-- I wonder if this can't be better coordinated with mpg, mph etc in earlier table--> | Non-SI abbreviation used for certain ]s. Link to ] on first use.<!--I wonder if this can't be better coordinated with mpg, mph, etc. in earlier table.-->
|- |-
|{{plainlist|
| imperial fluid ounce
* imperial fluid ounce
| {{ xt|imp fl oz}}
* imperial pint
| rowspan=8 | ''US'' or ''imperial/imp'' must be specified; ''fluid/fl'' must be specified, except with{{nbsp}}''gallon''. (Without ''fluid'', ] is ambiguous{{snd}}versus avoirdupois ounce or troy ounce{{snd}}and ] or ] is ambiguous{{snd}}versus US dry pint or US dry quart.)<!--<<Actually, I don't think //imperial fluid quart// or //imperial fluid pint// are correct -- from what I can see it's //imperial quart//, //imperial pint//, there being no imperial "dry" pints of quarts from which these need to be distinguished-->
* imperial quart
|-
| imperial fluid pint * imperial gallon
* US fluid ounce
| {{ xt|imp fl pt}}
* US dry pint
|-
* US liquid pint
| imperial fluid quart
* US dry quart
| {{ xt|imp fl qt}}
* US liquid quart
|-
| imperial gallon * US gallon
}}
| {{ xt|imp gal}}
|{{plainlist|
|-
* {{xt|imp fl oz}}
| US fluid ounce
| {{ xt|US fl oz}} * {{xt|imp pt}}
* {{xt|imp qt}}
|-
* {{xt|imp gal}}
| US fluid pint
| {{ xt|US fl pt}} * {{xt|US fl oz}}
* {{xt|US dry pt}}
|-
| US fluid quart * {{xt|US liq pt}}
| {{ xt|US fl qt}} * {{xt|US dry qt}}
* {{xt|US liq qt}}
|-
| US gallon * {{xt|US gal}}
}}
| {{ xt|US gal}}
|
*{{xtn|US}} or {{xtn|imperial}} (or {{xtn|imp}}) must be specified for all these units.
*{{xtn|fluid}} or {{xtn|fl}} must be specified for fluid ounces (to avoid ambiguity versus ] and ]).
*For US pints and quarts, {{xtn|dry}} or {{xtn|liquid}} ({{xtn|liq}}) are needed to be fully unambiguous, though context determines whether or not to repeat those qualifiers on every use in a given article.
|- |-
| cubic foot | cubic foot
| {{ xt|cu ft}} (''not'' {{!xt|cf}}) | {{xt|cu ft}} ({{em|not}} {{!xt|cf}})
| Write {{xt|five million cubic feet}}, {{xt|5,000,000{{nbsp}}cu{{nbsp}}ft}} or {{xt|{{val|5|e=6|u=cuft}}}}, not {{!xt|5{{nbsp}}MCF}}. | Write {{xt|five million cubic feet}}, {{xt|5,000,000{{nbsp}}cu{{nbsp}}ft}}, or {{xt|{{val|5|e=6|u=cuft}}}}, not {{!xt|5{{nbsp}}MCF}}.
|- |-
| cubic foot per second | {{nobr| cubic foot per second }}
| {{ xt|cu ft/s}} (''not'' {{!xt|cfs}}) | {{xt|cu ft/s}} ({{em|not}} {{!xt|cfs}})
| |
|- |-
| {{plainlist| | {{plainlist|
* litre * litre
* liter ''(U.S.)'' * liter {{em|(US)}}
}} }}
| {{ xt|l}} ''or'' {{xt|L}} | {{nobr|{{xt|L}} {{nobr|({{em|not}} {{!xt|l}} or {{!xt|ℓ}})}}}}
| The symbol l in isolation (i.e. not in such forms as ml) is easily mistaken for the digit 1 or the capital letter I. | The symbol l (lowercase "el") in isolation (i.e. outside forms as ml) is easily mistaken for the digit{{nbsp}}1 or the capital {{nobr|letter I ("eye")}} and should not be used.
|- |-
| {{plainlist|
| rowspan=7 | '''Mass'''<br />'''Force'''<br />'''Density'''<br />'''Pressure'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - -->
* millilitre
| ]
| {{ xt|long ton}} * milliliter {{em|(US)}}
}}
| rowspan=2 | Spell out in full.
| {{xt|ml}} or {{xt|mL}}
| Derivative units of the litre may use l (lowercase "el").
|- |-
| rowspan=7 {{Vert header|va=middle|<small>'''Mass, weight, force, density, pressure'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| ]
|{{plainlist|
| {{ xt|short ton}}
* gram
* kilogram
}}
|{{plainlist|
* {{xt|g}}
* {{xt|kg}}
}}
| Not {{!xt|gramme}}, {{!xt|kilogramme}}
|- |-
|{{plainlist|
| pound per square inch
* ]
| {{ xt|psi}}
* ]
|
}}
|{{plainlist|
* {{xt|long ton}}
* {{xt|short ton}}
}}
| Spell out in full.
|- |-
| {{plainlist| | {{plainlist|
* ] * ]
* ] ''(U.S.)'' * ] {{em|(US)}}
}} }}
| {{ xt|t}} {{nobr|(''not'' {{!xt|mt}} ''or'' {{!xt|MT}})}} | {{xt|t}} {{nobr|({{em|not}} {{!xt|mt}}, {{!xt|MT}}, or {{!xt|]}})}}
| |
|- |-
| {{nobr| pound per square inch }}
| troy ounce
| {{ xt|oz t}} | {{xt|psi}}
|
| rowspan=2 | ''t'' or ''troy'' must be specified. Articles about precious metals, black powder, and gemstones<!--is this list complete--> should always specify whether ounces and pounds are ] or ].
|- |-
|{{plainlist|
| troy pound
*troy ounce
| {{ xt|lb t}}
*troy pound
}}
|{{plainlist|
*{{xt|oz t}}
*{{xt|lb t}}
}}
|rowspan=2| The qualifier {{xtn|t}} or {{xtn|troy}} must be specified where applicable. Use the qualifier avdp (]) only where there is risk of confusion with troy ounce, imperial fluid ounce, US fluid ounce, or troy pound; but articles about precious metals, black powder, and gemstones<!--Is this list complete?--> should always specify which type of ounce (avoirdupois or ]) is being used, noting that these materials are normally measured in troy ounces and grams.
|-
|{{plainlist|
*avoirdupois ounce
*avoirdupois pound
}}
|{{plainlist|
*{{xt|oz}} or {{xt|oz avdp}}
*{{xt|lb}} or {{xt|lb avdp}}
}}
|- |-
| ] | ]
| {{ xt|carat}} | {{xt|carat}}
| Used to express masses of gemstones and pearls. | Used to express masses of gemstones and pearls.
|- |-
| '''Purity'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - --> | {{Vert header|va=middle|<small>'''Purity'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| ] | ]
| {{ xt|k}} ''or'' {{xt|Kt}} | {{nobr|{{xt|k}} or {{xt|Kt}} {{nobr|({{em|not}} {{!xt|]}} or {{!xt|]}})}}}}
| A measure of purity for gold alloys. (Do not confuse with the unit of mass with the same spelling.) | A measure of purity for gold alloys. (Do not confuse with the unit of mass with the same spelling.)
|- |-
| rowspan=3 {{Vert header|va=middle|<small>'''Time'''</small>}}
| rowspan=5 | '''Time'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - -->
| {{plainlist|
| second
* second
| {{ xt|s}}
* minute
|rowspan=3|Do not use <code>&amp;prime;</code> ({{!xt|&prime;}}), <code>&amp;Prime;</code> ({{!xt|&Prime;}}), apostrophe ({{!xt|'}}) or quote ({{!xt|"}}) for minutes or seconds. Use ''m'' for ''minute'' only where there is no danger of confusion with ''meter'', as in the hours{{ndash}}minutes{{ndash}}seconds formats for time durations described in the ].
* hour
|-
}}
| minute
| {{ xt|min}} | {{plainlist|
* {{xt|s}}
|-
* {{xt|min}}
| hour
| {{ xt|h}} * {{xt|h}}
}}
|Do not use <code>&amp;prime;</code>{{nbsp}}({{!xt|&prime;}}), <code>&amp;Prime;</code>{{nbsp}}({{!xt|&Prime;}}), apostrophe{{nbsp}}({{!xt|'}}) or quote{{nbsp}}({{!xt|"}}) for minutes or seconds. See also the hours–minutes–seconds formats for time durations described in the ].
|- |-
| rowspan=2|year | rowspan=2|year
| {{ xt|a}} | {{xt|a}}
| Use ''a'' only with an SI prefix ({{xt|a rock formation 540{{nbsp}}Ma{{nbsp}}old}},<!--<<perhaps this should be explained--> not {{!xt|Life expectancy rose to 60 a}}). | Use {{xtn|a}} only with an ] ({{xt|a rock formation 540{{nbsp}}Ma{{nbsp}}old}}, not {{!xt|Life expectancy rose to 60{{nbsp}}a}}).
|- |-
| {{ xt|y}} ''or'' {{xt|yr}} | {{xt|y}} or {{xt|yr}}
| {{crossref|See {{section link||Long periods of time}} for all affected units.}}
|
|- |-
| rowspan=4 <!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->{{Vert header|va=middle|<small>'''Information, data'''</small>}}
| rowspan=4 |
<small>'''Information'''</small><!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - -->
| bit | bit
| {{ xt|bit}} {{nobr|(''not'' {{!xt|b}} ''or'' {{!xt|B}})}} | {{xt|bit}} {{nobr|({{em|not}} {{!xt|b}} or {{!xt|B}})}}
| rowspan=4 | ''See also {{section link||Quantities of bytes and bits}}, below.'' | rowspan=4 | {{anchor|WP:MOSBPS}}{{crossref|See also {{section link||Quantities of bytes and bits}}, below.}} Do not confuse bit/second or byte/second with ].
|- |-
| byte | byte
| {{ xt|B}} ''or'' {{xt|byte}} {{nobr|(''not'' {{!xt|b}} ''or'' {{!xt|]}})}} | {{nobr| {{xt|B}} or {{xt|byte}} ({{em|not}} {{!xt|b}} or {{!xt|]}}) }}
|- |-
| bit per second | bit per second
| {{ xt|bit/s}} (''not'' {{!xt|bps}} or {{!xt|b/s}}) | {{xt|bit/s}} ({{em|not}} {{!xt|bps}}, {{!xt|b/s}})
|- |-
| byte per second | byte per second
| {{ xt|B/s}} ''or'' {{xt|byte/s}} {{nobr|(''not'' {{!xt|Bps}} ''or'' {{!xt|Bps}})}} | {{xt|B/s}} or {{xt|byte/s}} {{nobr|({{em|not}} {{!xt|Bps}}, {{!xt|bps}}, {{!xt|b/s}})}}
|- |-
| rowspan = 4 | '''Angle'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - --> | rowspan = 4 {{Vert header|va=middle|<small>'''Angle'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
|- |-
| ] | ]
| {{ xt|&prime;}} | {{xt|{{prime}}}}
| ]. ''Markup:'' <code>&amp;prime;</code>{{nbsp}} (not apostrophe/{{zwsp}}single quote{{nbsp}}{{!xt|'}}). No space between numerals and symbol {{nobr|({{xt|47&prime;}}, not {{!xt|47{{nbsp}}&prime;}})}} | Markup: <code>{{tl|prime}}</code>{{nbsp}} (] not apostrophe/{{zwsp}}single quote{{nbsp}}{{!xt|'}}). {{nobr|No space ({{xt|47{{prime}}}}, not {{!xt|47{{nbsp}}{{prime}}}}). }}
|- |-
| ] | ]
| {{ xt|&Prime;}} | {{xt|{{pprime}}}}
| ]. ''Markup:'' <code>&amp;Prime;</code>{{nbsp}} (not double-quote{{nbsp}}{{!xt|"}}). No space between numerals and symbol {{nobr|({{xt|22&Prime;}}, not {{!xt|22{{nbsp}}&Prime;}})}} | Markup: <code>{{tl|pprime}}</code>{{nbsp}} (] not double-quote{{nbsp}}{{!xt|"}}). {{nobr|No space ({{xt|22{{pprime}}}}, not {{!xt|22{{nbsp}}{{pprime}}}}). }}
|- |-
| degree | degree
| {{xt|&deg;}} | {{xt|°}}
| ''Markup:'' <code>&amp;deg;</code>{{nbsp}} (not ] {{!xt|&#186;}} or ]&nbsp;{{thinsp}}{{!xt|&#778;}}{{thinsp}}<!--<<thinsp is needed to prevent crash between ring and closing paren, at least on some browsers-->). No space between numerals and symbol {{nobr|({{xt|23&deg;}}, not {{!xt|23{{nbsp}}&deg;}})}} | Markup: degree ° not ] {{!xt|&#186;}} or ]{{nbsp}}{{thinsp}}{{!xt|&#778;}}. {{nobr|No space ({{xt|23°}}, not {{!xt|23{{nbsp}}°}}). }}
|- |-
| rowspan = 4 {{Vert header|va=middle|<small>'''Temperature'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| rowspan = 2 |
| degree Fahrenheit
<small>'''Temperature'''</small><!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS - - - -->
| {{xt|°F}} ({{em|not}} {{!xt|F}})
| degree
| rowspan = 3 | Markup: {{nobr|<code>12{{tl|nbsp}}°C</code>}}, not {{nobr|<s><code>12°C</code></s>}} or {{nobr|<s><code>12°{{t|nbsp}}C</code></s> }}. Do not use the ]s {{unichar|2103|Degree Celsius}} or {{unichar|2109|Degree Fahrenheit}}.
| {{xt|&deg;}}
|-
| rowspan = 2 | ''Markup:'' <code>&amp;deg;</code>. Nonbreaking space ({{tlx|nbsp}}) between numerals and symbol {{nobr|({{xt|40{{nbsp}}&deg;}}, not {{!xt|40&deg;}};}} {{nobr|{{xt|12{{nbsp}}&deg;C}}, not {{!xt|12&deg;C}}, nor {{!xt|12&deg;{{nbsp}}C}})}}
| degree ]
| {{xt|°R}} ({{em|not}} {{!xt|R}})
|-
| degree Celsius {{nobr|({{em|not}} degree centigrade)}}
| {{xt|°C}} ({{em|not}} {{!xt|C}})
|- |-
| degree Celsius {{nobr|(''not'' degree centigrade)}} | ] {{nobr|({{em|not}} degree kelvin)}}
| {{ xt|&deg;C}} (''not'' {{!xt|C}}) | {{xt|K}} ({{em|not}} {{!xt|°K}})
| Use a non-breaking space: <code><nowiki>12{{nbsp}}K</nowiki></code> (use ], not {{unichar|212A|KELVIN SIGN}}). When writing out the unit (not usually necessary), pluralize, e.g. {{xt|12 kelvins}} (see ])
|- |-
| rowspan = 2 | '''Energy'''<!-- - - - WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS- - - --> | rowspan = 2 {{Vert header|va=middle|<small>'''Energy'''</small>}}<!--WARNING! ADJUST ROWSPAN WHEN ADDING/REMOVING ROWS FROM A GROUP OF UNITS-->
| {{plainlist| | {{plainlist|
* ] * ]
Line 981: Line 1,227:
* gram calorie * gram calorie
}} }}
| {{ xt|cal}} | {{xt|cal}}
| rowspan=2 | In certain subject areas ''calorie'' is convention{{shy}}ally used alone. Articles following this practice should specify on first use whether the use refers to the small calorie or to the kilocalorie (large calorie). Providing conversions to SI units (usually calories to joules or kilocalories to kilojoules) may also be useful. A kilocalorie ({{xt|kcal}}) is 1000 calories. A calorie (small calorie) is the amount of energy required to heat 1 gram of water by 1 °C. A kilocalorie is therefore also a kilogram calorie. | rowspan=2 | In certain subject areas, ''calorie'' is convention{{shy}}ally used alone; articles following this practice should specify on first use whether the use refers to the small calorie or to the kilocalorie (large calorie). Providing conversions to ] units (usually calories to joules or kilocalories to kilojoules) may also be useful. A kilocalorie ({{xt|kcal}}) is 1000 calories. A calorie (small calorie) is the amount of energy required to heat 1 gram of water by 1{{nbsp}}°C. A kilocalorie is also a kilogram calorie.
|- |-
| {{plainlist| | {{plainlist|
Line 988: Line 1,234:
* large calorie * large calorie
* kilogram calorie * kilogram calorie
* {{nobr|(''not'' Caloriecan be ambiguous)}} * ({{em|not}} Calorie{{snd}}{{nobr|can be ambiguous)}}
}} }}
| {{ xt|kcal}} | {{xt|kcal}}
|} |}


====Quantities of bytes and bits <span id="Binary prefixes" />==== ==== Quantities of bytes and bits <span id="Binary prefixes"></span> ====

{{shortcut|WP:COMPUNITS}}
{{shortcut|MOS:COMPUNITS}}
In quantities of ]s and ]s, the prefixes ''kilo'' (symbol k or K), ''mega'' (M), ''giga'' (G), ''tera'' (T), etc. are ambiguous. They may be based on a decimal system (like the standard ] prefixes), meaning 10<sup>3</sup>, 10<sup>6</sup>, 10<sup>9</sup>, 10<sup>12</sup>, etc., or they may be based on a binary system, meaning 2<sup>10</sup>, 2<sup>20</sup>, 2<sup>30</sup>, 2<sup>40</sup>, etc. The binary meanings are more commonly used in relation to solid-state memory (such as ]), while the decimal meanings are more common for data transmission rates, disk storage and in theoretical calculations in modern academic textbooks.

In quantities of ] and ]s, the prefixes {{xtn|kilo-}} (symbol {{xtn|k}} or {{xtn|K}}), {{xtn|mega-}} ({{xtn|M}}), {{xtn|giga-}} ({{xtn|G}}), {{xtn|tera-}} ({{xtn|T}}), etc., are ambiguous in general usage. The meaning may be based on a decimal system (like the standard ] prefixes), meaning 10<sup>3</sup>, 10<sup>6</sup>, 10<sup>9</sup>, 10<sup>12</sup>, etc., or it may be based on a binary system, meaning 2<sup>10</sup>, 2<sup>20</sup>, 2<sup>30</sup>, 2<sup>40</sup>, etc. The binary meanings are more commonly used in relation to solid-state memory (such as ]), while the decimal meanings are more common for data transmission rates, disk storage and in theoretical calculations in modern academic textbooks.
{{Bit and byte prefixes}} {{Bit and byte prefixes}}
Follow these recommendations when using these prefixes in Misplaced Pages articles: Follow these recommendations when using these prefixes in Misplaced Pages articles:
* Following the SI standard, a lower-case {{xt|k}} should be used for "kilo-" whenever it means 1000 in computing contexts, whereas a capital {{xt|K}} should be used instead to indicate the binary prefix for 1024 according to JEDEC. If, under the exceptions detailed further below, the article otherwise uses IEC prefixes for binary units, use {{xt|Ki}} instead.

* Following the SI standard, a lower-case {{xt|k}} should be used for "kilo-" whenever it means 1000 in computing contexts, whereas a capital {{xt|K}} should be used instead to indicate the binary prefix for 1024 according to JEDEC. (If, under the exceptions detailed further below, the article otherwise uses IEC prefixes for binary units, use {{xt|Ki}} instead).
* Do not assume that the binary or decimal meaning of prefixes will be obvious to everyone. Explicitly specify the meaning of k and K as well as the primary meaning of M, G, T, etc. in an article ({{tlx|BDprefix}} is a convenient helper). Consistency within each article is desirable, but the need for consistency may be balanced with other considerations. * Do not assume that the binary or decimal meaning of prefixes will be obvious to everyone. Explicitly specify the meaning of k and K as well as the primary meaning of M, G, T, etc. in an article ({{tlx|BDprefix}} is a convenient helper). Consistency within each article is desirable, but the need for consistency may be balanced with other considerations.
* The definition most relevant to the article should be chosen as primary for that article, e.g. specify a binary definition in an article on RAM, decimal definition in an article on ], ]s, and a binary definition for Windows file sizes, despite files usually being stored on hard drives. * The definition most relevant to the article should be chosen as primary for that article, e.g. specify a binary definition in an article on RAM, decimal definition in an article on ], ]s, and a binary definition for Windows file sizes, despite files usually being stored on hard drives.
* Where consistency is not possible, specify wherever there is a deviation from the primary definition. * Where consistency is not possible, specify wherever there is a deviation from the primary definition.
* Disambiguation should be shown in bytes or bits, with clear indication of whether in binary or decimal base. There is no preference in the way to indicate the number of bytes and bits, but the notation style should be consistent within an article. Acceptable examples include: * Disambiguation should be shown in bytes or bits, with clear indication of whether in binary or decimal base. There is no preference in the way to indicate the number of bytes and bits, but the notation style should be consistent within an article. Acceptable examples include:
: &nbsp; &bull; &nbsp;{{xt|A 64{{nbsp}}MB ({{nowrap|64 &times; 1024<sup>2</sup>-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100 &times; 1000<sup>3</sup>-byte)}} hard drive}} ** {{xt|A 64{{nbsp}}MB ({{nowrap|64{{nbsp}}×{{nbsp}}1024<sup>2</sup>-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100{{nbsp}}×{{nbsp}}1000<sup>3</sup>-byte)}} hard drive}}
: &nbsp; &bull; &nbsp;{{xt|A 64{{nbsp}}MB ({{nowrap|64 &times; 2<sup>20</sup>-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100 &times; 10<sup>9</sup>-byte)}} hard drive}} ** {{xt|A 64{{nbsp}}MB ({{nowrap|64{{nbsp}}×{{nbsp}}2<sup>20</sup>-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100{{nbsp}}×{{nbsp}}10<sup>9</sup>-byte)}} hard drive}}
: &nbsp; &bull; &nbsp;{{xt|A 64{{nbsp}}MB (67,108,864-byte) video card and a 100{{nbsp}}GB (100,000,000,000-byte) hard drive}} ** {{xt|A 64{{nbsp}}MB {{nowrap|(67,108,864-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100,000,000,000-byte)}} hard drive}}
* Avoid inconsistent combinations such as {{!xt|A 64{{nbsp}}MB (67,108,864-byte) video card and a 100{{nbsp}}GB {{nowrap|(100 &times; 1000<sup>3</sup>-byte)}} hard drive}}. Footnotes, such as those seen in , may be used for disambiguation. * Avoid combinations with inconsistent form such as {{!xt|A 64{{nbsp}}MB {{nowrap|(67,108,864-byte)}} video card and a 100{{nbsp}}GB {{nowrap|(100{{nbsp}}×{{nbsp}}1000<sup>3</sup>-byte)}} hard drive}}. Footnotes, such as those seen in , may be used for disambiguation.
* Unless explicitly stated otherwise, one byte is eight bits (see ]). * Unless explicitly stated otherwise, one byte is eight bits (see {{crossref|{{section link|Byte|History}}}}).
*{{shortcut|MOS:BINPREFIX}}The ]es {{xtn|kibi-}} (symbol {{xtn|Ki}}), {{xtn|mebi-}} ({{xtn|Mi}}), {{xtn|gibi-}} ({{xtn|Gi}}), etc., are generally not to be used except:{{efn|1=Misplaced Pages follows common practice regarding ]s and other data traditionally quantified using ]es (e.g. {{xtn|mega-}} and {{xtn|kilo-}}, meaning 2<sup>20</sup> and 2<sup>10</sup> respectively) and their unit symbols (e.g. {{xtn|MB}} and {{xtn|KB}}) for RAM and ]es for most other uses. Despite the IEC's 1998 international standard creating several new binary prefixes (e.g. mebi-, kibi-, etc.) to distinguish the meaning of the decimal ]es (e.g. {{xtn|mega-}} and {{xtn|kilo-}}, meaning 10<sup>6</sup> and 10<sup>3</sup> respectively) from the binary ones, and the subsequent incorporation of these IEC prefixes into the ], consensus on Misplaced Pages in computing-related contexts favours the retention of the more familiar but ambiguous units {{xtn|KB}}, {{xtn|MB}}, {{xtn|GB}}, {{xtn|TB}}, {{xtn|PB}}, {{xtn|EB}}, etc. over use of unambiguous IEC binary prefixes. {{crossref|For detailed discussion, see ].}} }}
** when the majority of cited sources on the article topic use IEC prefixes;
** in a direct quote using the IEC prefixes;
** when explicitly discussing the IEC prefixes; or
** in articles in which both types of prefix are used with neither clearly primary, or in which converting all quantities to one or the other type would be misleading or lose necessary precision, or declaring the actual meaning of a unit on each use would be impractical.


==Currencies and monetary values<span id="Currencies"></span>==
The ]es ''kibi-'', ''mebi-'', ''gibi-'', etc. (symbols Ki, Mi, Gi, etc.) are rarely used, even in technical articles, so generally not to be used except:<ref>Misplaced Pages follows common practice regarding ]s and other data traditionally quantified using ]es (e.g. mega- and kilo-, meaning 2<sup>20</sup> and 2<sup>10</sup> respectively) and their unit symbols (e.g. MB and KB) for RAM and ]es for most other uses. Despite the IEC's 1998 international standard creating several new binary prefixes (e.g. mebi-, kibi-) to distinguish the meaning of the decimal ]es (e.g. mega- and kilo-, meaning 10<sup>6</sup> and 10<sup>3</sup> respectively) from the binary ones, and the subsequent incorporation of these IEC prefixes into the ] (ISQ), consensus on Misplaced Pages in computing-related contexts currently favours the retention of the more familiar but ambiguous units "KB", "MB", "GB", "TB", "PB", "EB", etc. over use of unambiguous IEC binary prefixes. For detailed discussion, see ].</ref>
* when the majority of cited sources on the article topic use IEC prefixes,
* in a direct quote using the IEC prefixes,
* when explicitly discussing the IEC prefixes,
* in articles in which both types of prefix are used with neither clearly primary, or in which converting all quantities to one or the other type would be misleading or lose necessary precision, or declaring the actual meaning of a unit on each use would be impractical.


{{shortcut|MOS:$|MOS:&pound;|MOS:€|MOS:CURRENCY|MOS:MONEY}}
===Unit conversions===
{{redirect-multi|2|WP:MONEY|WP:CURRENCY|the WikiProject focusing on articles about currencies|Misplaced Pages:WikiProject Numismatics}}
{{shortcut|MOS:CONVERSIONS|WP:MOSCONVERSIONS}}
{{redirect2|WP:$|WP:£|the policy on paid editing|Misplaced Pages:Paid-contribution disclosure|the humor page|Help:Buying Misplaced Pages}}
Where English-speaking countries use different units for the same quantity, follow the "primary" quantity with a conversion in parentheses: {{xt|the Mississippi River is {{convert|2320|mi|km|0}} long}}; {{xt|the Murray River is {{convert|2375|km|mi|0}} long}}. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so.
* Where an ] is not part of the ], or vice-versa{{mdashb}}and in particular, where those systems give a single term different definitions{{mdashb}}a double conversion may be appropriate: {{xt|Rosie weighed {{convert|80|kg|lb stlb}}}} (markup: <code><nowiki>{{convert|80|kg|lb stlb}}</nowiki></code>); {{xt|{{nobr|The car}} had a fuel economy of {{convert|5|L/100km|mpgus mpgimp|abbr=on}}}} (markup: <code><nowiki>{{convert|5|L/100km|mpgus mpgimp|abbr=on}}</nowiki></code>).
* Generally, conversions to and from metric units and US or imperial units should be provided, except:
** When inserting a conversion would make a common or linked expression awkward ({{xt|The four-minute mile}}).
** When units are part of the subject of a topic{{mdashb}}nautical miles in articles about the history of nautical law ({{xt|5 nautical miles}}), SI units in scientific articles ({{xt|a 600-kilometer asteroid}}), yards in articles about American football{{mdashb}}it can be excessive to provide conversions every time a unit occurs. It could be best to note that this topic will use the units (possibly giving the conversion factor to another familiar unit in a parenthetical note or a footnote), and link the first occurrence of each unit but not give a conversion every time it occurs.
* Converted quantity values should use a level of '''precision''' similar to that of the source quantity value, so {{xt|the Moon is 380,000{{nbsp}}kilometres (240,000{{nbsp}}mi) from Earth}}, not {{!xt|(236,121{{nbsp}}mi)}}. Small numbers may need to be converted to a range where rounding would cause a significant distortion, so {{xt|one mile (1–2{{nbsp}}km)}}, not {{!xt|one mile (2{{nbsp}}km)}}. Be careful especially when your source has already converted from the units you're now converting back to. This may be evidenced by multiples of common conversion factors in the data, such as 160 km (from 100 miles). See ].
* ] can be used to convert and format many common units, including {{tlx|convert}}, which includes non-breaking spaces.
* In a '''direct quotation''', always retain the source units. Any conversions can be supplied either in the quote itself (in square brackets, following the original measurement) or in a footnote. See ] and ].
* {{tlx|Units attention}} may be added to articles needing general attention regarding choice of units and unit conversions.


'''Choice of currency'''<!-- >>>>>>>> Headings in this section formatted using bold, instead of he usual === style, as permitted by MOS:PSEUDOHEAD: "If you want to reduce the size of the table of contents (TOC), use {{TOC limit}} ... In cases where {{TOC limit}} cannot be used because of lower-level headings elsewhere in the article, then using bold for the sub-sub-sub headings causes the least annoyance for screen reader users a rarity."-->
==<span id="Currencies" /> Currencies and monetary values==
{{shortcut|WP:$|WP:&pound;|WP:€|MOS:CURRENCY}}
{{see also|Misplaced Pages:WikiProject Numismatics/Style#Article titles}}
===Choice of currency===
* In '''country-specific articles''', such as ], use the currency of the subject country. * In '''country-specific articles''', such as ], use the currency of the subject country.
* In '''non-country-specific articles''' such as ], use US dollars ({{xt|$123}}), euros ({{xt|&euro;123}}), or pounds sterling ({{xt|&pound;123}}). * In '''non-country-specific articles''', such as ], use US dollars ({{xt|US$123}} on first use, generally {{xt|$123}} thereafter), euros ({{xt|&euro;123}}), or pounds sterling ({{xt|&pound;123}}).


===Currency names=== '''Currency names'''
* Do not capitalize the names of currencies, currency subdivisions, coins and banknotes except e.g. at the start of a sentence.<!--It's a bit more complicated than this -- clearly "Australain dollar" uses a capital on Austrailian"--> * Do not capitalize the names or denominations of currencies, currency subdivisions, coins and banknotes: not {{!xt|a Five-Dollar bill, four Quarters, and one Penny total six Dollars one Cent}} but {{xt|a five-dollar bill, four quarters, and one penny total six dollars one cent}}. ''Exception:'' where otherwise required, as at the start of a sentence or in such forms as {{xt|Australian dollar}}.
* To pluralize ''euro'' use the standard English plurals ({{xt|ten euros and fifty cents}}), not the ] ({{!xt|ten euro and fifty cent}}). For the adjectival form, use a hyphenated singular: ({{xt|a two-euro pen}};{{nbsp}}{{nbsp}} {{xt|a ten-cent coin}}). * To pluralize {{xtn|euro}}, use the standard English plurals ({{xt|ten euros and fifty cents}}), not the ] ({{!xt|ten euro and fifty cent}}). For the adjectival form, use a hyphenated singular ({{xt|a two-euro pen and a ten-cent coin}}).
* Link the first occurrence of lesser-known currencies ({{xt|]s}}).<!--should a symbol be introduced at this time?--> * Link the first occurrence of lesser-known currencies (e.g. {{xt|]s}}).<!--Should a symbol be introduced at this time?-->


===Currency symbols===<!--symbols? signifiers? abbreviations? see ] and ]s--> '''Currency symbols'''{{anchor|Currency symbols}}<!--Symbols, signifiers, abbreviations? See ] and ]s.-->
* In general, the first mention of a particular currency should use its full, unambiguous signifier (e.g. {{xt|A$52}}), with subsequent references using just the appropriate symbol (e.g. {{xt|$88}}), unless this would be unclear. ''Exceptions:'' * In general, the first mention of a particular currency should use its full, unambiguous signifier (e.g. {{xt|{{A$|52|link=yes}}}}), with subsequent references using just the appropriate symbol (e.g. {{xt|$88}}), unless this would be unclear. {{em|Exceptions:}}
:* In an article referring to multiple currencies represented by the same symbol (e.g. the dollars of the US, Canada, Australia, New Zealand, and other countries{{snd}}see {{section link|Currency symbols|dollar variants}}) use the full signifier (e.g. {{xt|US$}}, {{xt|A$}}) each time, except (possibly) where a particular context makes this both unnecessary and undesirable. ** In an article referring to multiple currencies represented by the same symbol (e.g. the dollars of the US, Canada, Australia, New Zealand, and other countries{{snd}}{{crossref|see {{section link|Currency symbols|dollar variants}}}}) use the full signifier (e.g. {{xt|US$}} or {{xt|A$}}, but not e.g. {{!xt|$US123}} or {{!xt|$123 (US)}}) each time, except (possibly) where a particular context makes this both unnecessary and undesirable.
:* In articles entirely on EU-, UK- and/or US-related topics, all occurrences may be shortened ({{xt|&euro;26}}, {{xt|&pound;22}} or {{xt|$34}}), unless this would be unclear. ** In articles entirely on US-related topics, all occurrences of the ] may be shortened ({{xt|$34}}), unless this would be unclear.
** For currencies that use a unit named the "]":
* The ] is represented by the {{xt|&pound;}} symbol, with one horizontal bar. The double-barred {{!xt|&#8356;}} symbol is ambiguous, as it has also been used for the ] and other currencies. For non-British currencies that use pounds or a pound symbol (e.g. the ], IR&pound;) use the symbol convention{{shy}}ally preferred for that currency.<!--If no modern currency still uses the ₤ symbol, the developers should be asked to remove it from the edit tool box to prevent its misuse.-->
*** Use the {{xt|£}} symbol ({{unichar|00A3|pound sign}}) for unambiguous referrals to ], the United Kingdom's currency. Avoid the {{!xt|{{unichar|20A4|lira sign}}}}.{{efn|Whether 00A3 is displayed with one or two bars is typeface (font) dependent.}}
* If there is no common English abbreviation or symbol, follow the ] standard. See also ].
*** {{xt|GBP}}, sterling's ISO 4217 code, should be used to disambiguate that currency from others. Avoid using {{xt!|stg.}} or {{xt!|GB£}}.{{efn|See also ].}}
*** For currencies other than sterling, use the symbol or abbreviation conventionally employed for that currency, if any.
* Link the first occurrence of lesser-known currency symbols (e.g. {{xt|]}})
* If there is no common English abbreviation or symbol, follow the ] standard. {{crossref|See also ].}}
{{see also|Misplaced Pages:Manual of Style/Abbreviations#Unicode abbreviation ligatures}}
{{Anchor|Formatting of monetary values}}'''Currency formatting'''


* A point (full stop or period, <code>.</code>){{snd}}never a comma{{snd}}is used as the decimal marker ({{xt|$6.57}}, not {{!xt|$6,57}}).
==={{Anchor|Formatting of monetary values}}Formatting===
{{Anchor|Format}}<!--Old, imprecise heading, may be linked to.-->
* A period (full stop) is used as the decimal point{{mdashb}}never a comma ({{xt|$6.57}}, not {{!xt|$6,57}}).
* For the grouping of digits (e.g. {{xt|&pound;1,234,567}}) see {{section link||Grouping of digits}}, above. * For the grouping of digits (e.g. {{xt|&pound;1,234,567}}) see {{section link||Grouping of digits}}, above.
* Do not place a currency symbol ''after'' the accompanying numeric figures (e.g. {{!xt|123$}}, {{!xt|123&pound;}}, {{!xt|123&euro;}}) unless that is the normal convention for that currency when writing in English.{{clarify|reason=please give an example}} Never use forms such as {{!xt|$US123}} or {{!xt|$123 (US)}}. * Do not place a currency symbol {{em|after}} the accompanying numeric figures (e.g. {{!xt|123$}}, {{!xt|123&pound;}}, {{!xt|123&euro;}}) unless that is the normal convention for that symbol when writing in English: {{xt|smaller British coins include 1p, 2p, and 5p denominations}}.
* Currency abbreviations that come before the numeric value are ''unspaced'' if they consist of a nonalphabetic symbol only, or end in a symbol ({{xt|&pound;123}};{{nbsp}}{{nbsp}} {{xt|&euro;123}}); but ''spaced'' if alphabetic ({{xt|R{{nbsp}}75}}). * Currency abbreviations preceding a numeric value are {{em|unspaced}} if they consist of a nonalphabetic symbol alone ({{xt|&pound;123}} or {{xt|&euro;123}}), or end with a nonalphabetic symbol ({{xt|{{R$|link=yes|123}}}}); but {{em|spaced}} (using {{t|nbsp}}) if completely alphabetic ({{xt|{{currency|123|ZAR}}}} or {{xt|{{currency|123|JOD}}}}).
* Ranges should be expressed giving the currency signifier just once: {{xt|$250{{ndash}}300}}, not {{!xt|$250{{ndash}}$300}}. * Ranges should be expressed giving the currency signifier just once: {{xt|{{val|p=$|250|{{ndash}}|300}}}}, not {{!xt|{{val|p=$|250}}{{ndash}}{{val|p=$|300}}}}.
* ''million'' and ''billion'' should be spelled out on first use, and (optionally) abbreviated ''M'' or ''bn'' (both unspaced) thereafter: {{xt|She received &pound;70 million and her son &pound;10M}}; {{xt|the school's share was $250{{ndash}}300 million, and the charity's $400{{ndash}}450M}}. * {{xt|million}} and {{xt|billion}} should be spelled out on first use, and (optionally) abbreviated {{xt|M}} or {{xt|bn}} (both unspaced) thereafter: {{xt|She received &pound;70 million and her son &pound;10M}}; {{xt|the school's share was {{val|p=$|250|{{ndash}}|300 |u=million}}, and the charity's $400{{ndash}}450M.}}
* In general, a currency symbol should be accompanied by a numeric amount e.g. not {{!xt|He converted his US$ to A$}} but {{xt|He converted his US dollars to Australian dollars}} or {{xt|He exchanged the US$100 note for Australian dollars}}. * In general, a currency symbol should be accompanied by a numeric amount e.g. not {{!xt|He converted his {{US$}} to {{A$}}}} but {{xt|He converted his US dollars to Australian dollars}} or {{xt|He exchanged the {{US$|100}} note for Australian dollars}}.
:* Exceptions may occur in tables and infoboxes where space is limited e.g. {{xt|''Currencies accepted for deposit:'' ], ], ], ]}}. It may be appropriate to wikilink such uses, or add an explanatory note. ** Exceptions may occur in tables and infoboxes where space is limited e.g. {{xt|Currencies accepted: ], ], ], ]}}. It may be appropriate to wikilink such uses, or add an explanatory note.


'''Currency conversions'''{{anchor|Currency conversions}}
===Conversions===
* Conversions of '''less-familiar currencies''' may be provided in terms of more familiar currencies{{mdashb}}such as the US dollar, euro or pound sterling{{mdashb}}using an appropriate rate (which is often ''not'' the current exchange rate). Conversions should be in parentheses after the original currency, rounding to avoid ] (two significant digits is usually sufficient, as most exchange rates fluctuate significantly), with at least the year given as a rough point of conversion rate reference; e.g. {{xt|Since 2001 the grant has been 10,000,000 ] ($1.4M, &euro;1.0M, or &pound;800k {{as of|2009|08|lc=on}})}}, not {{!xt|($1,390,570, &euro;971,673 or &pound;848,646)}}.<!-- is "800k" really acceptable?--> * Conversions of {{em|lesser-known currencies}} may be provided in terms of more familiar currencies{{snd}}such as the US dollar, euro or pound sterling{{snd}}using an appropriate rate (which is often {{em|not}} the current exchange rate). Conversions should be in parentheses after the original currency, along with the convert-to year; e.g. {{xt|the grant in 2001 was 10,000,000 ] ($1.4M, &euro;970,000, or &pound;850,000 {{as of|2009|lc=on}})}}
* For '''obsolete currencies''', provide an equivalent (formatted as a conversion) if possible, in the modern replacement currency (e.g. decimal pounds for historical pre-decimal pounds-and-shillings), or a US-dollar equivalent where there is no modern equivalent. * For {{em|obsolete currencies}}, provide an equivalent (formatted as a conversion) if possible, in the modern replacement currency (e.g. euros for amounts denominated in ]), or a US-dollar equivalent where there is no modern equivalent.
* In some cases it may be appropriate to provide a conversion accounting for inflation or deflation over time. See {{tlx|Inflation}} and {{tlx|Inflation-fn}}. * In some cases, it may be appropriate to provide a conversion accounting for inflation or deflation over time. {{crossref|See {{tlx|Inflation}} and {{tlx|Inflation-fn}}.}}
* When converting among currencies or inflating/deflating, it is rarely appropriate to give the converted amount to more than three significant figures; typically, only two significant figures are justified: {{xt|the grant in 2001 was 10,000,000 ] ($1.4M, &euro;970,000, or &pound;850,000)}}, not {{!xt|($1,390,570, &euro;971,673 or &pound;848,646)}}

==Common mathematical symbols<span id="Minus sign"></span>==


==<span id="Minus sign" />Common mathematical symbols==
{{shortcut|WP:COMMONMATH||MOS:MINUS}} {{shortcut|WP:COMMONMATH||MOS:MINUS}}
{{See also|Misplaced Pages:Manual of Style/Mathematics}} {{See also|Misplaced Pages:Manual of Style/Mathematics|Misplaced Pages:Manual of Style#Common mathematical symbols|Help:Displaying a formula}}
* The ''Insert'' menu below the editing window gives a more complete list of math symbols, and allows symbols to be inserted without the HTML encoding (e.g. <code>&amp;divide;</code>) shown here.
* This is not a complete list of symbols that may be used.
* Spaces are placed to left and right when a symbol is used with {{nobr|]}}, but no space with {{nobr|]}} * Spaces are placed to left and right when a symbol is used {{nobr|]}} ({{xt|the sum 4 + 5}}), but no space is used when {{nobr|]}} ({{xt|the value{{nbsp}}+5}}). ''Exception:'' spaces are usually omitted in inline fractions formed with <code>/</code>: {{xt|3/4}} not {{!xt|{{nobr|3 / 4}}}}.
* The {{tlx|mvar}} (for single-letter variables) and {{tlx|math}} (for more complicated expressions) templates are available to display mathematical formulas in a manner distinct from surrounding text.
* The {{tlx|nbsp}} and {{tlx|nowrap}} templates may be used to prevent awkward linebreaks in mathematical material.
* The {{tlx|nbsp}} and {{tlx|nowrap}} templates may be used to prevent awkward linebreaks.

{{clear right}} {{clear right}}
{|class="wikitable" style="align: center; text-align: center;" {|class="wikitable" style="align: center; text-align: center;"
Line 1,078: Line 1,323:
! Comments ! Comments
|- |-
| rowspan=2| ] | rowspan=2| ]
| ''x'' + ''y'' | {{math|''x'' + ''y''}}
| <code><nowiki>''x'' + ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' + ''y''}}</syntaxhighlight>
| rowspan=2| | rowspan=2|
|- |-
| +''y'' | {{math|+''y''}}
| <syntaxhighlight lang="wikitext" inline>{{math|+''y''}}</syntaxhighlight>
| <code><nowiki>+''y''</nowiki></code>
|- |-
| rowspan=2|] | rowspan=2|]
| ''x'' &minus; ''y'' | {{math|''x'' &minus; ''y''}}
| <code><nowiki>''x'' &amp;minus; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &minus; ''y''}}</syntaxhighlight>
| rowspan=2|Do not use hyphen ({{!xt|<code>-</code>}}) or dashes ({{!xt|{{tlx|ndash}}}} {{nobr|or {{!xt|{{tlx|mdash}}}}).}} | rowspan=2|Do not use hyphens ({{!xt|<syntaxhighlight lang="wikitext" inline>-</syntaxhighlight>}}) or dashes ({{!xt|{{tlx|ndash}}}} {{nobr|or {{!xt|{{tlx|mdash}}}}).}}
|- |-
| &minus;''y'' | {{math|&minus;''y''}}
| <code><nowiki>&amp;minus;''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|&minus;''y''}}</syntaxhighlight>
|- |-
| rowspan=2| ] | rowspan=2| ]
| 41.5 &plusmn; 0.3 | 41.5 &plusmn; 0.3
| <code><nowiki>41.5 &amp;plusmn; 0.3</nowiki></code> | <syntaxhighlight lang="wikitext" inline>41.5 &plusmn; 0.3</syntaxhighlight>
| rowspan=2| | rowspan=2|
|- |-
| {{nobr|1= &minus;(&plusmn;''a'') = &#8723;''a'' }} | {{math|1={{nobr|1= &minus;(&plusmn;''a'') = &mnplus;''a''}}}}
| {{nobr| <code><nowiki>&amp;minus;(&amp;plusmn;''a'') = &amp;#8723;''a''</nowiki></code> }} | {{nobr|1=<syntaxhighlight lang="wikitext" inline>{{math|1=&minus;(&plusmn;''a'') = &#8723;''a''}}</syntaxhighlight> }}
|- |-
| ],<br />cross | ],<br>]
| ''x'' &times; ''y'' | {{math|''x'' &sdot; ''y''}}
| <code><nowiki>''x'' &amp;times; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &sdot; ''y''}}</syntaxhighlight>
| Do not use the letter "x" to indicate multiplication. However, an unspaced "x" may be used as a substitute for "by" in common terms such as "]". | rowspan=2|Do not use the letter {{!xt|x}} to indicate multiplication. However, an {{em|unspaced}} {{xt|x}} may be used as a substitute for "by" in common terms such as ].
|- |-
| ], obelus | ],<br>cross
| ''x'' &divide; ''y'' | {{math|''x'' &times; ''y''}}
| <code><nowiki>''x'' &amp;divide; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &times; ''y''}}</syntaxhighlight>
|-
| rowspan=8|
| ], ]
| {{math|''x'' &divide; ''y''}}
| <syntaxhighlight lang="wikitext" inline>{{math|''x'' &divide; ''y''}}</syntaxhighlight>
|
|- |-
| ] | ]
| ''x'' = ''y'' | {{math|1=''x'' = ''y''}}
| <syntaxhighlight lang="wikitext" inline>{{math|1=''x'' = ''y''}}</syntaxhighlight> or<br><syntaxhighlight lang="wikitext" inline>{{math|''x'' {{=}} ''y''}}</syntaxhighlight>
| <code><nowiki>''x'' = ''y''</nowiki></code>
| Note the use of <syntaxhighlight lang="wikitext" inline>1=</syntaxhighlight> or <syntaxhighlight lang="wikitext" inline>{{=}}</syntaxhighlight> to make the template parameters work correctly
|- |-
| ] | ]
| ''x'' &ne; ''y'' | {{math|''x'' &ne; ''y''}}
| <code><nowiki>''x'' &amp;ne; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &ne; ''y''}}</syntaxhighlight>
| rowspan=6|
|- |-
| ] | ]
| {{pi}} &asymp; 3.14 | {{math|''&pi;'' &asymp; 3.14}}
| <syntaxhighlight lang="wikitext" inline>{{math|''&pi;'' &asymp; 3.14}}</syntaxhighlight>
| <code><nowiki>{{pi}} &amp;asymp; 3.14</nowiki></code><!-- should the pi be italic? -->
|- |-
| ] | ]
| ''x'' &lt; ''y'' | {{math|''x'' &lt; ''y''}}
| <code><nowiki>''x'' &amp;lt; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &lt; ''y''}}</syntaxhighlight>
|- |-
| ] | ]
| ''x'' &le; ''y'' | {{math|''x'' &le; ''y''}}
| <code><nowiki>''x'' &amp;le; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &le; ''y''}}</syntaxhighlight>
|- |-
| ] | ]
| ''x'' &gt; ''y'' | {{math|''x'' &gt; ''y''}}
| <code><nowiki>''x'' &amp;gt; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &gt; ''y''}}</syntaxhighlight>
|- |-
| ] | ]
| ''x'' &ge; ''y'' | {{math|''x'' &ge; ''y''}}
| <code><nowiki>''x'' &amp;ge; ''y''</nowiki></code> | <syntaxhighlight lang="wikitext" inline>{{math|''x'' &ge; ''y''}}</syntaxhighlight>
|} |}


==Geographical coordinates== ==Geographical coordinates==
<div style="float:right; width:100px;">{{Shortcut|WP:Coordinates|MOS:COORDS}}</div>


{{Shortcut|MOS:COORDS|MOS:COORDINATES}}
:'''For draft guidance on, and examples of, coordinates for linear features, see ]'''.

:{{crossref|For draft guidance on, and examples of, coordinates for linear features, see ].}}


:'''Quick guide''': :'''Quick guide''':


{{coord how-to}} {{coord how-to}}
] on Earth should be entered using a template to standardise the format and to provide a link to maps of the coordinates. As long as the templates are adhered to, a robot performs the functions automatically.
] on Earth should be entered using a template to standardise the format and to provide a link to maps of the coordinates. As long as the templates are adhered to, a robot performs the functions automatically.


First, ]. Avoid ]. First, ]. Avoid ].


The {{tlx|Coord}} template offers users a choice of display format through ], emits a ], and is recognised (in the {{em|title}} position) by the "nearby" feature of Misplaced Pages's mobile apps and by external service providers such as Google Maps and Google Earth, and Yahoo. Infoboxes automatically emit {{tlx|Coord}}.
Two types of template are available:
* {{tlx|coord}} offers users a choice of display format through ]s, emits a ], and is recognised (in the ''title'' position) by the "nearby" feature of Misplaced Pages's mobile apps and by external partners such as Google (-Maps and -Earth) and Yahoo.
* Infoboxes such as {{tlx|Infobox settlement}}, which automatically emit {{tlx|Coord}}.


The following formats are available. The following formats are available.
* For degrees only (including decimal values): {{tlc|coord|2={{var|dd}}|3={{var|N/S}}|4={{var|dd}}|5={{var|E/W}}}} * For degrees only (including decimal values): {{tlc|coord|2={{var|dd}}|3={{var|N/S}}|4={{var|dd}}|5={{var|E/W}}}}
* For degrees/minutes: {{tlc|coord|2={{var|dd}}|3={{var|mm}}|4={{var|N/S}}|5={{var|dd}}|6={{var|mm}}|7={{var|E/W}}}} * For degrees/minutes: {{tlc|coord|2={{var|dd}}|3={{var|mm}}|4={{var|N/S}}|5={{var|dd}}|6={{var|mm}}|7={{var|E/W}}}}
Line 1,165: Line 1,414:
where: where:
* {{var|dd}}, {{var|mm}}, {{var|ss}} are the degrees, minutes and seconds, respectively; * {{var|dd}}, {{var|mm}}, {{var|ss}} are the degrees, minutes and seconds, respectively;
* {{var|N/S}} is either ''N'' for northern or ''S'' for southern ]s; * {{var|N/S}} is either <kbd>N</kbd> for northern or <kbd>S</kbd> for southern ]s;
* {{var|E/W}} is either ''E'' for eastern or ''W'' for western ]s; * {{var|E/W}} is either <kbd>E</kbd> for eastern or <kbd>W</kbd> for western ]s;
* negative values may be used in lieu of ''S'' and ''W'' to denote Southern and Western ]s * negative values may be used in lieu of <kbd>S</kbd> and <kbd>W</kbd> to denote Southern and Western ]


For example: For example:


The city of ], located at '''59° 55&prime; N, 10° 44&prime; E''', enter: For the city of ], located at 59° 54&prime; 50&Prime; N, 10° 45&prime; 8&Prime; E:
: <code><nowiki>{{coord|59|55|N|10|44|E}}</nowiki></code>{{mdashb}}which becomes {{coord|59|55|N|10|44|E}} : <code><nowiki>{{coord|59|54|50|N|10|45|08|E}}</nowiki></code>{{snd}}which becomes {{coord|59|54|50|N|10|45|08|E}}


For a country, like ], less precision is appropriate: For a country, like ], with no source on an exact geographic center, less precision is appropriate due to uncertainty:
: <code><nowiki>{{coord|22|S|24|E}}</nowiki></code>{{mdashb}}which becomes {{coord|22|S|24|E}} : <code><nowiki>{{coord|22|S|24|E}}</nowiki></code>{{snd}}which becomes {{coord|22|S|24|E}}


Higher levels of precision are obtained by using seconds: Higher levels of precision are obtained by using seconds:
: <code><nowiki>{{coord|33|56|24|N|118|24|00|W}}</nowiki></code>{{mdashb}}which becomes {{coord|33|56|24|N|118|24|00|W}} : <code><nowiki>{{coord|33|56|24|N|118|24|00|W}}</nowiki></code>{{snd}}which becomes {{coord|33|56|24|N|118|24|00|W}}


Coordinates can be entered as decimal values Coordinates can be entered as decimal values:
: <code><nowiki>{{coord|33.94|S|118.40|W}}</nowiki></code>{{mdashb}}which becomes {{coord|33.94|S|118.40|W}} : <code><nowiki>{{coord|33.94|S|118.40|W}}</nowiki></code>{{snd}}which becomes {{coord|33.94|S|118.40|W}}


Increasing or decreasing the number of decimal places controls the precision. Trailing zeros should be used as needed to ensure that both values have the same level of precision. Increasing or decreasing the number of decimal places controls the precision. Trailing zeros may be added as needed to give both values the same appearance.


], ], ] and ] are examples of articles that contain geographical coordinates. ], ], ] and ] are examples of articles that contain geographical coordinates.


Generally, the larger the object being mapped, the ''less precise'' the coordinates should be. For example, if just giving the location of a city, precision greater than 100{{nbsp}}meters is not needed unless specifying a particular point in the city, for example the central administrative building. Specific buildings or other objects of similar size would justify precisions down to 10{{nbsp}}meters or even one meter in some cases (1′′ ~15{{nbsp}}m to 30{{nbsp}}m, 0.0001° ~5.6{{nbsp}}m to 10{{nbsp}}m). Generally, the larger the object being mapped, the {{em|less precise}} the coordinates should be. For example, if just giving the location of a city, precision greater than degrees (°), minutes (&prime;), seconds (&Prime;) is not needed, which suffice to locate, for example, the central administrative building. Specific buildings or other objects of similar size would justify precisions down to 10{{nbsp}}meters or even one meter in some cases (1″ ~15{{nbsp}}m to 30{{nbsp}}m, 0.0001° ~5.6{{nbsp}}m to 10{{nbsp}}m).


The final field, following the E/W, is available for attributes such as ''type'', ''region'' and ''scale''. The final field, following the E/W, is available for attributes such as <code>type:</code>, <code>region:</code>, or <code>scale:</code> {{crossref|(the codes are documented at {{section link|Template:Coord/doc#Coordinate parameters}})}}.


When adding coordinates, please remove the {{tlx|coord missing}} tag from the article, if present. When adding coordinates, please remove the {{tlx|coord missing}} tag from the article, if present (often at the top or bottom).


For more information, see ]. {{Crossref|For more information, see ].}}


Templates other than {{tlx|coord}} should use the following variable names for coordinates: {{var|lat_d}}, {{var|lat_m}}, {{var|lat_s}}, {{var|lat_NS}}, {{var|long_d}}, {{var|long_m}}, {{var|long_s}}, {{var|long_EW}}. Templates other than {{tlx|coord}} should use the following variable names for coordinates: {{var|lat_d}}, {{var|lat_m}}, {{var|lat_s}}, {{var|lat_NS}}, {{var|long_d}}, {{var|long_m}}, {{var|long_s}}, {{var|long_EW}}.


==See also== ==See also==

* ]
* ] * ]
* ] at Meta * ] at Meta
* {{section link|m:Help:Calculation|Displaying numbers and numeric expressions}} at Meta * {{section link|m:Help:Calculation|Displaying numbers and numeric expressions}} at Meta
{{Math templates}}


==Notes and references== ==Notes==

{{Notelist|35em}}

==References==

{{Reflist|35em}} {{Reflist|35em}}
{{Style wide}}


{{Manual of Style}}
]
{{Math templates}}

] ]
] ]

Latest revision as of 11:21, 4 January 2025

Misplaced Pages project page "WP:NUMBERS" redirects here. For other uses, see WP:NUMBERS (disambiguation).
This guideline is a part of the English Misplaced Pages's Manual of Style.
It is a generally accepted standard that editors should attempt to follow, though occasional exceptions may apply. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page.
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Where this manual gives options, maintain consistency within an article unless there is a good reason to do otherwise. The Arbitration Committee has ruled that editors should not change an article from one guideline-defined style to another without a substantial reason unrelated to mere choice of style; edit-warring over optional styles is unacceptable. If discussion fails to resolve the question of which style to use in an article, defer to the style used by the first major contributor.

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Quotations, titles, etc.

See also: Misplaced Pages:Manual of Style § Quotations

Quotations, titles of books and articles, and similar "imported" text should be faithfully reproduced, even if they use formats or units inconsistent with these guidelines or with other formats in the same article. If necessary, clarify via , article text, or footnotes.

Non-breaking spaces

Guidance on the use of non-breaking spaces ("hard spaces") is given in some sections below, but not all situations in which hard spaces ({{nbsp}} or &nbsp;) or {{nowrap}} may be appropriate are described. For further information see Misplaced Pages:Manual of Style § Non-breaking spaces and Misplaced Pages:Line-break handling.

Chronological items

Statements likely to become outdated

Shortcuts See also: Misplaced Pages:Manual of Style/Words to watch § Relative time references, Misplaced Pages:Updating information, and Misplaced Pages:As of

Except on pages that are inherently time-sensitive and updated regularly (e.g. the "Current events" portal), terms such as now, today, currently, present, to date, so far, soon, upcoming, ongoing, and recently should usually be avoided in favor of phrases such as during the 2010s, since 2010, and in August 2020. Wording can usually be modified to remove the "now" perspective: not she is the current director but she became director on 1 January 2025; not 2010–present but beginning in 2010 or since 2010. Terms likely to go out of date include best known for, holds the record for, etc. For current and future events, use phrases such as as of January 2025 or since the beginning of 2025 to signal the time-dependence of the information; use the template {{as of}} (or {{updated}}) in conjunction. Relative-time expressions are acceptable for very long periods, such as geological epochs: Humans diverged from other primates long ago, but only recently developed state legislatures.

Dates, months, and years

"WP:YEAR" redirects here. For WikiProject Years, see WP:YEARS. Shortcuts

Formats

Acceptable date formats
General use Only in limited situations
where brevity is helpful
Comments
2 September 2001 2 Sep 2001 A comma doesn't follow the year unless otherwise required by context:
  • The 5 May 1922 meeting was cancelled.
  • Except Jones, who left London on 5 March 1847, every delegate attended the signing.
September 2, 2001 Sep 2, 2001 A comma follows the year unless other punctuation obviates it:
  • The weather on March 12, 2005, was clear and warm.
  • Everyone remembers July 20, 1969 – when humans first landed on the Moon.
2 September 2 Sep Omit year only where there is no risk of ambiguity:
  • The 2012 London Olympics ran from 25 July to 12 September.
  • January 1 is New Year's Day.
September 2 Sep 2
No equivalent for general use 2001-09-02 Use yyyy-mm-dd format only with Gregorian dates from 1583 onward.
September 2001 Sep 2001
Shortcut

Shortcuts

Unacceptable date formats (except in external titles and quotes)
Unacceptable Corrected Comments
Sep. 2 Sep 2 Do not add a full stop (period) to an abbreviated month or to the day-of-month.
9. June 9 June or June 9
9 june
june 9
Months should be capitalized.
9th June
June 9th
the 9th of June
Do not use ordinals (1st, 2nd, 3rd, etc.).
09-06
06-09
Do not use these formats.
09 June
June 09
Do not zero-pad day ...
2007-4-15 2007-04-15 ... except in all-numeric (yyyy-mm-dd) format, in which month and day are zero-padded to two digits.
2007/04/15 Do not use separators other than hyphens.
20070415 Do not omit hyphens.
07-04-15 Do not abbreviate year.
15-04-2007
04-15-2007
2007-15-04
Do not use dd-mm-yyyy, mm-dd-yyyy or yyyy-dd-mm formats.
2007 April 15
2007 Apr 15
Do not use these formats.
7/2001
7-2001
07-2001
2001-07
2001 July
July of 2001
July 2001 Do not use these formats.
July, 2001 No comma between month and year.
3 July, 2001 3 July 2001
July 3 2001 July 3, 2001 Comma required between day and year.
the '97 elections
the 97 elections
the 1997 elections Do not abbreviate year.
Copyright MMII Copyright 2002 Roman numerals are not normally used for dates.
Two thousand one 2001 Years and days of the month are not normally written in words.
the first of May
May the first
1 May or May 1
June 0622 June 622 Do not zero-pad years.
June 2,015 June 2015 Do not add a comma to a four-digit year.
sold in the year 1995 sold in 1995 Write "the year" only where needed for clarity (About 200 ships arrived in the year 300).
Consistency

Shortcut
  • Dates in article body text should all use the same format: She fell ill on 25 June 2005 and died on 28 June, not She fell ill on 25 June 2005 and died on June 28.
  • Publication dates in an article's citations should all use the same format, which may be:
    • the format used in the article body text,
    • an abbreviated format from the "Acceptable date formats" table, provided the day and month elements are in the same order as in dates in the article body
    • the format expected in the citation style being used (but all-numeric date formats other than yyyy-mm-dd must still be avoided).
    For example, publication dates within a single article might be in one, but only one, of these formats (among others):
    • Jones, J. (20 September 2008)
    • Jones, J. (September 20, 2008)
    If an article uses a template such as {{Use mdy dates}} or {{Use dmy dates}}, then Citation Style 1 and 2 templates automatically render dates (|date=, |access-date=, |archive-date=, etc) in the specified format, regardless of the format they are entered in. (The |cs1-dates= parameter can be used to fine-tune the generated output, see Template:Use mdy dates § Auto-formatting citation template dates.)
  • Access and archive dates in an article's citations should all use the same format, which may be:
    • the format used for publication dates in the article (see above);
    • the format expected in the citation style adopted in the article; or
    • yyyy-mm-dd
    For example, access/archive dates within a single article might be in one, but only one, of these formats (among others):
    • Jones, J. (September 20, 2008) ... Retrieved February 5, 2009.
    • Jones, J. (20 Sep 2008) ... Retrieved 5 Feb 2009.
    • Jones, J. (20 September 2008) ... Retrieved 2009-02-05.
    When a citation style does not expect differing date formats, it is permissible to normalize publication dates to the article body text date format, and/or access/archive dates to either, with date consistency being preferred.
Strong national ties to a topic
Shortcut

Articles on topics with strong ties to a particular English-speaking country (see Misplaced Pages:Manual of Style § Strong national ties to a topic) should generally use the date format most commonly used in that country.

  • For the United States this is MDY (July 4, 1976)
  • For most other English-speaking countries it is DMY (4 July 1976).
  • Articles relating to Canada may use either format with (as always) consistency within each article. (see § Retaining existing format, below)
  • Shortcut However, in certain topic areas, it is customary to use a date format different from the usual national one. For example, articles (including biographical articles) on the modern US military should use DMY dates, in accordance with US military usage.

In articles without strong ties to a particular English-speaking country, the choice of date format and the choice of national variety of English are independent and unrelated.

Retaining existing format
Shortcuts See also: Misplaced Pages:Manual of Style § Retaining existing styles
  • If an article has evolved using predominantly one date format, this format should be used throughout the article, unless there are reasons for changing it based on the topic's strong ties to a particular English-speaking country, or consensus on the article's talk page.
  • The date format chosen in the first major contribution in the early stages of an article (i.e., the first non-stub version) should continue to be used, unless there is reason to change it based on the topic's strong ties to a particular English-speaking country, or consensus on the article's talk page.
  • Where an article has shown no clear sign of which format is used, the first person to insert a date is equivalent to "the first major contributor".

Era style

"WP:BCE" redirects here. For the copyediting guide, see Misplaced Pages:Basic copyediting. Shortcuts
  • The default calendar eras are Anno Domini (BC and AD) and Common Era (BCE and CE). Either convention may be appropriate for use in Misplaced Pages articles depending on the article context. Apply Misplaced Pages:Manual of Style § Retaining existing styles with regard to changes from one era to the other.
    • Use either the BC–AD or the BCE–CE notation consistently within the same article. Exception: do not change direct quotations, titles, etc.
    • An article's established era style should not be changed without reasons specific to its content; seek consensus on the talk page first (applying Misplaced Pages:Manual of Style § Retaining existing styles) by opening a discussion under a heading using the word era, or another similarly expressive heading, and briefly stating why the style should be changed.
    • BCE and CE or BC and AD are written in upper case, unspaced, without a full stop (period), and separated from the numeric year by a space (5 BC, not 5BC). It is advisable to use a non-breaking space.
    • AD appears before or after a year (AD 106, 106 AD); BCE, CE, and BC always appear after (106 CE, 3700 BCE, 3700 BC).
    • In general, omit CE or AD, except to avoid ambiguity or awkwardness.
      • Typically, write The Norman Conquest took place in 1066 not 1066 CE or AD 1066.
      • But Plotinus lived at the end of the 3rd century AD (not simply at the end of the 3rd century) may avoid confusion unless the era is clear from context.
      • One- and two-digit years may look more natural with an era marker (born in 2 AD or born January 15, 22 CE, not born in 2 nor January 15, 22).
      • Ranges beginning in BC / BCE should specify the ending era: write 450 to 200 BCE or 450 BC to 200 BC or 450 BCE to 200 CE, but not 450 BCE to 200. (see Ranges)
  • Uncalibrated (BCE) radiocarbon dates: Calibrated and uncalibrated dates can diverge widely, and some sources distinguish the two only via BCE or BC (for calibrated dates) versus bce or bc (uncalibrated). When feasible, avoid uncalibrated dates except in direct quotations, and even then ideally give the calibrated date in a footnote or square-bracketed note – , or at least indicate the date type – . This also applies to other dating systems in which a calibration distinction is drawn.
  • BP or YBP: In scientific and academic contexts, BP (Before Present) or YBP (years Before Present) are often used. (Present in this context by convention refers to January 1, 1950.) Write 3000 years BP or 3000 YBP or 3000 years before present but not forms such as 3000 before present and 3000 years before the present. If one of the abbreviated forms is used, link to Before Present on first use: The Jones artifact was dated to 4000 YBP, the Smith artifact to 5000 YBP.
  • Other era systems may be appropriate in an article. In such cases, dates should be followed by a conversion to Anno Domini or Common Era, and the first instance linked: Qasr-al-Khalifa was built in 221 AH (836 CE), or in 836 AD (221 AH).
    • Astronomical year numbering is similar to the Common Era. There is no need to follow a year expressed with astronomical year numbering with a conversion to Common Era. The first instance of a non-positive year should still be linked: The March equinox passed into Pisces in year −67. (The expressions −67 and 68 BCE refer to the same year.)

Julian and Gregorian calendars

Shortcuts See also: Old Style and New Style dates

A date can be given in any appropriate calendar, as long as it is (at the minimum) given in the Julian calendar or the Gregorian calendar or both, as described below. For example, an article on the early history of Islam may give dates in both Islamic and Julian calendars. Where a calendar other than the Julian or Gregorian is used, the article must make this clear.

  • Current events are dated using the Gregorian calendar.
  • Dates of events in countries using the Gregorian calendar at that time are given in the Gregorian calendar. This includes some of the Continent of Europe from 1582, the British Empire from 14 September 1752, and Russia from 14 February 1918 (see Adoption of the Gregorian calendar).
  • Dates before 15 October 1582 (when the Gregorian calendar was first adopted in some places) are normally given in the Julian calendar.
  • Dates after 4 October 1582 in a place where the Julian calendar was observed should be given in the Julian calendar.
  • For either the Julian or Gregorian calendars, the beginning of the year should be treated as 1 January even if a different start-of-year date was observed in the place being discussed.
  • Dates for Roman history before 45 BC are given in the Roman calendar, which was neither Julian nor Gregorian. When (rarely) the Julian equivalent is certain, it may be included.
  • For dates in early Egyptian and Mesopotamian history, Julian or Gregorian equivalents are often uncertain. Follow the consensus of reliable sources, or indicate their divergence.

The dating method used should follow that used by reliable secondary sources (or if reliable sources disagree, that used most commonly, with an explanatory footnote). The guidance above is in line with the usage of reliable sources such as American National Biography, Oxford Dictionary of National Biography, and Encyclopædia Britannica.

Where it is not obvious that a given date should be given in Julian alone or in Gregorian alone, consider giving both styles, for example by using {{OldStyleDate}}. If a date appears without being specified as Old Style or New Style, tagging that date with {{which calendar?}} will add the page to Category:Articles containing ambiguous dates for further attention.

If an article contains Julian calendar dates after 4 October 1582 (as in the October Revolution), or if a start-of-year date other than 1 January was in force in the place being discussed, or both, a footnote should be provided on the first usage, explaining the calendar usage adopted for the article. The calendar usage should be compatible with this guideline.

Ranges

Shortcuts See also: Misplaced Pages:Manual of Style § Number ranges "MOS:DIED" redirects here. For euphemisms for "died", see Misplaced Pages:Manual of Style/Words to watch § Euphemisms.
  • A simple year–year range is written using an en dash (, &ndash; or {{ndash}}, or {{nbnd}} for a non-breaking en dash), not an em dash, hyphen, or slash; this dash is unspaced (that is, with no space on either side); and the end year is usually given in full:
    • 1881–1882;  1881–1886 (not 1881–86);  1881–1892 (not 1881–92)
      • Markup: 1881{{ndash}}1882 or 1881&ndash;1882
    • Although non-abbreviated years are generally preferred, two-digit ending years (1881–82, but never 1881–882 or 1881–2) may be used in any of the following cases: (1) two consecutive years; (2) infoboxes and tables where space is limited (using a single format consistently in any given table column); and (3) in certain topic areas if there is a very good reason, such as matching the established convention of reliable sources. For consistency, avoid abbreviated year ranges when they would be used alongside non-abbreviated ranges within an article (or related pages, if in titles). Never use abbreviated years for ranges across centuries (1999–2000, not 1999–00) or for years from the first millennium (886–887, not 886–87).
    • The slash notation (2005/2006) may be used to signify a fiscal year or other special period, if that convention is used in reliable sources.
  • Other "simple" ranges use an unspaced en dash as well:
    • day–day: 5–7 January 1979;  January 5–7, 1979;  elections were held March 5–8.
    • month–month: the 1940 peak period was May–July;  the peak period was May–July 1940;  (but the peak period was May 1940 – July 1940 uses a spaced en dash; see below)
  • In certain cases where at least one item on either side of the en dash contains a space, then a spaced en dash ({{snd}}) is used. For example:
    • between specific dates in different months: They travelled June 3 – August 18, 1952;  They travelled 3 June – 18 August 1952
    • between dates in different years:
      • Charles Robert Darwin (12 February 1809 – 19 April 1882) was an English naturalist ...
        • Markup: 12{{nbsp}}February 1809{{snd}}19{{nbsp}}April 1882 or 12&nbsp;February 1809&nbsp;&ndash; 19&nbsp;April 1882
      • Abraham Lincoln (February 12, 1809 – April 15, 1865) was the 16th president of ...
    • between months in different years: The exception was in force August 1892 – January 1903;  The Ghent Incursion (March 1822 – January 1, 1823) was ended by the New Year's Treaty
      • Markup: March 1822{{snd}}January{{nbsp}}1, 1823 or March 1822&nbsp;&ndash; January&nbsp;1, 1823
    • Where era designations, c. or other modifiers are present (see § Uncertain, incomplete, or approximate dates):
      • if the modifier applies to only one of the two endpoints of the range, use a spaced en dash: 150 BCE – 50 BCE, 5 BC – 12 AD, c. 1393 – 1414
      • if the modifier applies to the range as a whole, disregard the modifier: 150–50 BCE, reigned 150 BCE – 50 BCE, reigned 150–50 BCE, r. c. 1393 – 1414, r. 1393–1414.
  • Use an en dash, or a word such as from or between, but not both: from 1881 to 1886 (not from 1881–1886);  between June 1 and July 3 (not between June 1 – July 3)
Shortcuts

  • MOS:DATED says "terms such as ... 'present' should usually be avoided". For ranges, if "to present" or "–present" is used, the current year (or, in cases where necessary, date) of "present" at the time of writing should be included. Thus 1982–present (as of 2025) – if writing in 2025 – is preferable to 1982–present. If the "from" date has an internal space, a spaced en dash is used. Other constructions may be more appropriate in prose (see § Statements likely to become outdated). An alternative form is Since 1982.
In tables and infoboxes where space is limited, pres. may be used (1982–pres.). Do not use incomplete-looking constructions such as 1982– and 1982–... .
  • Consider adding the {{As of}}, or {{Update after}} templates to such constructions, depending on how important it is for editors to keep "present" up to date.
  • For a person still living: Serena Williams (born September 26, 1981) is a ..., not (September 26, 1981 – ) or (born on September 26, 1981).

    Do not use * to indicate born; use b. only where space is limited, e.g., in tables and infoboxes; use either born or b. consistently in any given table column.

  • Where birthdate is unknown: John Smith (died May 1, 1622) or John Smith (died 1622)

    Do not use to indicate died; use d. only where space is limited, with consistency within any given table column.

  • An overnight period may be expressed using a slash between two contiguous dates: the night raids of 30/31 May 1942 or raids of 31 May / 1 June 1942.

    Or use an en dash: (unspaced) raids of 30–31 May 1942;  (spaced) raids of 31 May – 1 June 1942.

  • The {{Age}} template can keep ages current in infoboxes and so on:
    • {{age|1989|7|23}} returns: 35
    • {{age|1989|7|23}}-year-old returns: 35-year-old
    • {{age|1989|7|23}} years old returns: 35 years old
  • Date mathematics templates are available for other age calculations.

Uncertain, incomplete, or approximate dates

Shortcuts
  • To indicate "around", "approximately", or "about", the use of the {{circa}} template is preferred at first occurrence over just c. At later occurrences, c. is preferred over circa, c, ca, ca., around, approximately, or approx.:
    • John Sayer (c. 1750 – 2 October 1818) ...
    • the Igehalkid dynasty of Elam, c. 1400 BC ...
  • Where both endpoints of a range are approximate, c. should appear before each date (the two-argument form of {{circa}} does this):
    • Dionysius Exiguus (c. 470 – c. 540) ... (not Dionysius Exiguus (c. 470 – 540) ...)
    • Rameses III (reigned c. 1180 – c. 1150 BCE) ... (not Rameses III (reigned c. 1180 – 1150 BCE) ...)
  • Where birth/death limits have been inferred from known dates of activity:
    • Offa of Mercia (before 734 – 26 July 796) ...
    • Robert Menli Lyon (1789 – after 1863) ...
    • Ambrose Gwinnett Bierce (June 24, 1842 – after December 26, 1913) ...
  • When birth and death dates are unknown, but the person is known to have been active ("flourishing") during certain years, fl., ], or {{fl.}} may be used:
    • Jacobus Flori (fl. 1571–1588) ...
    • Jacobus Flori fils (fl. c. 1600 – 1616) ...
The corresponding template {{r.}} produces reign output: r. 540–562, though it is often clearer to write out reigned 540–562, especially in the lead. With both of these templates, linked forms should not be used on disambiguation pages, and "active" followed by the range is a better alternative for occupations not relating to the composition of works, whether it be musical, grammatical, historical, or any other such work.
  • When a date is known to be either of two years (e.g. from a regnal or AH year conversion, or a known age at death):
    • Anne Smith (born 1912 or 1913; died 2013) ...
  • Other forms of uncertainty should be expressed in words, either in article text or in a footnote: April 14, 1224 (unattested date). Do not use a question mark (1291?), because it fails to communicate the nature of the uncertainty.
  • Where c. or a similar form appears which applies only to one of the two endpoints of the range, use a spaced en dash ({{snd}}).
    • Examples: 1896 – after 1954, 470 – c. 540, c. 470 – 540, c. 470 – c. 540.
    • Markup: 1896{{snd}}after 1954, 470{{snd}}{{c.|540}}, {{c.|470}}{{snd}}540, {{c.|470|540}}.
  • Where a modifier applies to the range as a whole, such as fl. and r., use a spaced or unspaced en dash as appropriate to the range if this modifier is disregarded.
    • Examples: fl. 1571–1588, fl. c. 1600 – 1616, r.c. 1353 – 1336 BC, r. 1989–2019 CE, r. 2019 CE – present.
  • Some modifiers, such as traditionally, around, BH, and CE, sometimes apply to only one endpoint, and sometimes to the whole range. Whether the en dash should be spaced or unspaced should still be determined by the above guidelines, but consider rephrasing if the result is ambiguous or possibly confusing.
    • traditionally 1571–1588 and traditionally 1571 – 1588 mean two different things, which may not be obvious to the reader.
    • traditionally 1585 – c. 1590 can have two different meanings, and which one is meant may not be clear.
    • 400 BCE – 200 clearly has BCE applying only to one endpoint, but the range is ambiguous. Consider using 400–200 BCE, 400 BCE – 200 BCE, or 400 BCE – 200 CE, depending on what is meant.
    • Technically, Taishō 13 – 57 is currently unambiguous (because there is no Taishō 57), but it is better to use both era designations in this case: Taishō 13 – Shōwa 57.
  • Ideally a non-breaking space should follow very short modifiers such as c., fl., r., b., and d.

Times of day

Shortcuts

Context determines whether the 12- or 24-hour clock is used. In all cases, colons separate hours, minutes, and (where present) seconds, e.g. 1:38:09 pm or 13:38:09. Use figures (11 a.m. or 12:45 p.m.) rather than words (twelve forty-five p.m.).

  • 12-hour clock times end with lower-case a.m. or p.m., or am or pm, preceded by a non-breaking space, e.g. 2:30 p.m. or 2:30 pm (markup: 2:30{{nbsp}}p.m. or 2:30{{nbsp}}pm), not 2:30p.m. or 2:30pm. Hours should not have a leading zero (e.g. 2:30 p.m., not 02:30 p.m.). Usually, use noon and midnight rather than 12 pm and 12 am; whether "midnight" refers to the start or the end of a date should be explicitly specified unless clear from the context. Where several times that are all a.m. or all p.m. appear in close proximity, then a.m. or p.m. need be given only once if there is no risk of confusion.
  • 24-hour clock times have no a.m., p.m., noon or midnight suffix, and include a colon (15:30 not 1530). Hours under 10 should have a leading zero (08:15). The time 00:00 refers to midnight at the start of a date, 12:00 to noon, and 24:00 to midnight at the end of a date, but 24 should not be used for the first hour of the next day (e.g. use 00:10 for ten minutes after midnight, not 24:10).

Time zones

Shortcut

Give dates and times appropriate to the time zone where an event took place. For example, the date of the attack on Pearl Harbor should be December 7, 1941 (Hawaii time/​date). Give priority to the place at which the event had its most significant effects; for example, if a hacker in Monaco attacked a Pentagon computer in the US, use the time zone for the Pentagon, where the attack had its effect. In some cases, the best solution may be to add the date and time in Coordinated Universal Time (UTC). For example:

     8 p.m. Eastern Standard Time on January 15, 2001 (01:00 UTC, January 16)

Alternatively, include just the UTC offset:

     21:00 British Summer Time (UTC+1) on 27 July 2012

Rarely, the time zone in which an event took place has since changed; for example, China until 1949 was divided into five time zones, whereas all of modern China is one time zone; UTC+8. Similarly, the term "UTC" is not appropriate for dates before this system was adopted in 1960; Universal Time (UT) is the appropriate term for the mean time at the prime meridian (Greenwich) when it is unnecessary to specify the precise definition of the time scale. Be sure to show the UTC or offset appropriate to the clock time in use at the time of the event, not the modern time zone, if they differ.

Days of the week

  • Where space is limited (e.g. tables), days of the week may be abbreviated as Sun, Mon, Tue, Wed, Thu, Fri, Sat (without dots, i.e. not Sun., Mon., etc.).

Seasons of the year

Shortcut
  • Avoid using seasons to refer to a particular time of year, as they are often unduly ambiguous: Spring 1995 began in the Southern Hemisphere six months after it did in the Northern Hemisphere; winter spans two calendar years in the Northern Hemisphere, but not in the Southern Hemisphere. Moreover, areas near the Equator have only wet and dry seasons. Unambiguous alternatives include early 1995; the second quarter of 1995; March to June 1995; spent the southern autumn in Antarctica.
    • Referring to a season by name is appropriate when it is part of a conventional name or designation (annual mid-winter festival; the autumn harvest; the court's winter term; the magazine's summer 2015 issue).
  • Season names are generally not capitalized (a hot summer), except when personified (Old Man Winter) or when part of a formal name (2018 Winter Olympics; Arab Spring) that is capitalized under the guidelines for capitalization. They are capitalized when part of the title of a work (Science Fiction Quarterly, Summer 1942), except that seasonal editions may be lower-cased in running text (the Summer 1985 issue of Interzone or the summer 1985 issue of Interzone).

Decades

Shortcuts
  • To refer to a decade as a chronological period per se (not with reference to a social era or cultural phenomenon), always use four digits and an s, as in the 1980s. Do not use the 1980's, or the 1980‑ies.
    • Prefixes should be hyphenated (the mid‑1980s;  pre‑1960s social attitudes).
    • Adjectives should not be hyphenated (the late 1950s, the early 1970s).
  • For a social era or cultural phenomenon associated with a particular decade:
    • Two digits (with a preceding apostrophe) may be used as an alternative to four digits, but only in well-established phrases seen in reliable sources: the Roaring '20s; the Gay '90s; condemning the '60s counterculture—but grew up in 1960s Boston, moving to Dallas in 1971. Do not write: the 90's; the 90s; or the 90s'.
    • Another alternative (where seen in reliable sources) is to spell the decade out, capitalized: changing attitudes of the Sixties.

Centuries and millennia

Shortcuts

The sequence of numbered years in dates runs ... 2 BC, 1 BC, 1 AD, 2 AD ...; there is no "year zero".

  • Treat the 1st century AD as years 1–100, the 17th century as 1601–1700, and the second millennium as 1001–2000; similarly, the 1st century BC / BCE was 100–1 BC / BCE, the 17th century BC / BCE was 1700–1601 BC / BCE, and the second millennium 2000–1001 BC / BCE.
  • Centuries and millennia are identified using either Arabic numerals (the 18th century) or words (the second millennium), with in-article consistency (MOS:ORDINAL notwithstanding). When used adjectivally they contain a hyphen (nineteenth-century painting or 19th-century painting). Do not use superscripts (19 century).
  • Do not capitalize (the best Nineteenth-century paintings; during the Nineteenth Century).
  • Do not use Roman numerals (XVIII century).
  • The 18th century refers to the period (1701–1800), while strictly the 1700s refers either to (1700–1799) or (1700–1709)
    • When using forms such as the 1900s, ensure there is no ambiguity as to whether the century or the decade is meant.
  • See WP:Manual of Style § En dashes for use of hyphens and dashes in obscure situations.

Long periods of time

Numbers

"MOS:FIGURE" redirects here. Not to be confused with MOS:IMAGE.

Numbers as figures or words

Shortcuts

Information on specific situations is scattered elsewhere on this page.

Generally, in article text:

  • Integers from zero to nine are spelled out in words.
  • Integers greater than nine expressible in one or two words may be expressed either in numerals or in words (16 or sixteen, 84 or eighty-four, 200 or two hundred). When written as words, integers from 21 to 99 that are not multiples of 10 are hyphenated (including when part of a larger number): fifty-six and fifty-six thousand, but five hundred and five thousand.

Shortcut

Notes and exceptions:

  • Avoid beginning a sentence with a figure:
    • Use: There were many matches; 23 ended in a draw. Or: There were many matches. Twenty-three ended in a draw.
    • Not: There were many matches. 23 ended in a draw.
    • Use: No elections were held in 1945 and 1950.
    • Not: 1945 and 1950 had no elections. (Nor: Nineteen forty-five and 1950 had no elections—comparable numbers near one another should all be written in words or all in figures.)
  • In tables and infoboxes, quantities are expressed in figures (Years in office: 5); but numbers within a table's explanatory text and comments follow the general rule.
  • Numbers in mathematical formulae are never spelled out (3 < π < ⁠22/7⁠ not three < pi < twenty-two sevenths), and "numbers as numbers" are rarely spelled out in other mathematical contexts (the first three primes are 2, 3, and 5 not the first three primes are two, three, and five; but zero-sum game and roots of unity).
  • Sport scores and vote tallies should be given as numerical figures (a 25–7 victory; passed with 7 ayes, 2 nays, and 1 abstention, though passed with 7 ayes, 2 nays, and no abstentions would be acceptable, instead of ... 0 abstentions).
  • Comparable values near one another should be all spelled out or all in figures, even if one of the numbers would normally be written differently: patients' ages were five, seven, and thirty-two or ages were 5, 7, and 32, but not ages were five, seven, and 32.
    • Similar guidance applies where "mixed units" are used to represent a single value (as is often done with time durations, and in the imperial and US customary systems): 5 feet 11 inches tall; five feet eleven inches tall; 3 minutes 27 seconds; three minutes twenty-seven seconds.
  • Adjacent quantities not comparable should ideally be in different formats: twelve 90-minute volumes or 12 ninety-minute volumes, not 12 90-minute volumes or twelve ninety-minute volumes.
    • Avoid awkward juxtapositions: On February 25, 2011, twenty-one more were chosen, not On February 25, 2011, 21 more were chosen.
  • Sometimes figures and words carry different meanings; for example, Every locker except one was searched implies there is a single exception (without specifying which), while Every locker except 1 was searched implies that locker number 1 was the only locker not searched.
  • Proper names, technical terms, and the like are never altered: 10 Downing StreetNine Inch NailsChannel 8C7 vertebraThe Sixth SenseChanel No. 5Fourth EstateThe Third ManSecond ComingFirst AmendmentZero Hour!,  "Less than Zero".
  • Figures as figures: Use a figure when the figure itself (its glyph, shape, etc.) is meant: a figure-8 pattern; in the shape of the numeral 6. (See Misplaced Pages:Manual of Style/Text formatting § Words as words.)
  • Only figures are used with unit symbols (12 min not twelve min); but figures or words may be used with unit names (12 minutes or twelve minutes), subject to the provisions above.

Other numbers

  • Other numbers are given in numerals (3.75, 544) or in forms such as 21 million (or billion, trillion, etc. – but rarely thousand or hundred). Markup: 21{{nbsp}}million
    • Billion and trillion are understood to represent their short-scale values of 10 (1,000,000,000) and 10 (1,000,000,000,000), respectively. Keep this in mind when translating articles from non-English or older sources.
    • M (unspaced, capitalized) or bn (unspaced), respectively, may be used for "million" or "billion" after a number, when the word has been spelled out at the first occurrence (Her estate of £61 million was split among her husband (£1M), her son (£5M), her butler (£10M), and her three Weimaraners (£15M each).).
    • SI prefixes and symbols, such as mega- (M), giga- (G) and tera- (T), should be used only with units of measure as appropriate to the field and not to express large quantities in other contexts. Examples of misuse: In a population of 1.3G people, 300 megadeaths would be expected.
    • Sometimes, the variety of English used in an article may suggest the use of a numbering system other than the Western thousands-based system. For example, the Indian numbering system is conventionally used for certain things (especially monetary amounts) in South Asian English. This is discouraged in Misplaced Pages articles by WP:Manual of Style § Opportunities for commonality.
      • When it is done anyway, for contextually important reasons, link the first spelled-out instance of each quantity (e.g. ], which yields: crore). If no instances are spelled out, provide a note after the first instance, directing the reader to the article about the numbering system.
      • Provide a conversion to Western numbers for the first instance of each quantity (For Indian figures, the templates {{lakh}} and {{crore}} may be used for this purpose), and provide conversions for subsequent instances if they do not overwhelm the content of the article. For example, write three crore (thirty million). When converting a currency amount, use the exchange rate that applied at the time being written about; the {{FXConvert}} template can be used for this purpose, or specialized templates for a currency such as {{INRConvert}} (for Indian Rupees) or {{KRWConvert}} (for Korean Won) can be used.
      • Group digits in Western thousands-based style (e.g., 30,000,000; not 3,00,00,000); see § Delimiting (grouping of digits), below.
      • An article's variety of English does not uniquely determine its formatting of numbers. Other considerations – such as conventions used in mathematics, science, and engineering – may also apply. In general, choice and order of formats and conversions is a matter of editorial discretion and consensus at the article.
Shortcut

Ordinals

"MOS:1ST" redirects here. For the guideline on the first sentence in articles, see MOS:FIRST.
  • The general principles set out in § Numbers as figures or words apply to ordinals. In particular, do not start a sentence with a figure, and generally use first through ninth, not 1st through 9th, for single-digit ordinals.
  • In "suffix" forms, use two-letter suffixes: 1st, 2nd, 3rd, 4th and so on (2nd Battalion not 2d Battalion). Do not superscript (e.g. 123).
  • Do not use ordinals for dates (see MOS:BADDATE).
  • In English text, do not use a dot (.) or the ordinal indicator (º). The masculine º or feminine ª ordinal indicator is acceptable in names, quotations, etc. from languages that conventionally use it. An Italian example: 313º Gruppo Addestramento Acrobatico not 313º Acrobatic Training Group or the 313º. Use HTML markup for languages that do not have a special character but conventionally use a superscript, like 2 in French.
  • Regnal numbers are normally written with ASCII Roman numerals (without suffix, e.g. Elizabeth II not Elizabeth IInd or Elizabeth 2nd).

Number ranges

Shortcuts

Like date ranges, number ranges and page ranges should state the full value of both the beginning and end of the range, separated by an en dash: pp. 1902–1911 or entries 342–349. Except within quotations, avoid abbreviated forms such as 1902–11 or 342–9, which are not understood universally, are sometimes ambiguous, and can cause inconsistent metadata to be created in citations.

Sport scores, vote tallies, etc.

Shortcuts

Sport scores, vote tallies, or other presentations that juxtapose two opposing quantities use an unspaced en dash:

  • Smith beat Jones 7–3.
  • Polls predicted Alice would defeat Bob 74–20 percent, with 6 percent undecided.

To avoid potential line breaks, use {{nowrap}} around the entire score construction, or use {{nbnd}} instead of {{ndash}}.

Singular versus plural

  • Nouns following simple fractions are singular (took 1⁄4 dose;  net change was −1⁄2 point;  3⁄2 dose).
  • Nouns following mixed numbers are plural (11⁄2 doses;  another 43⁄4 miles).
  • Nouns following the lone, unsigned digit 1 (one) are singular, but those following other decimal numbers (i.e. base-10 numbers not involving fractions) are plural (increased 0.7 percentage points;  365.25 days;  paid 5 dollars per work hour, 1 dollar per travel hour, 0 dollars per standby hour;  increased by 1 point but net change +1 points;  net change −1 points;  net change 1.0 points).
  • The same rules apply to numbers given in words (one dose;  one and one-half doses;  zero dollars;  net change of negative one points).

Fractions and ratios

Shortcuts
  • Where numerator and denominator can each be expressed in one word, a fraction is usually spelled out (e.g. a two-thirds majority;  moved one-quarter mile); use figures if a fraction appears with a unit symbol (e.g. 1⁄4 mi (markup: {{frac|1|4}}&nbsp;mi), not a quarter of a mi or one-quarter mi). A common exception is a series of values: The distances were 1+1⁄4, 2⁄3 and 1⁄2 mile, respectively.
  • Mixed numbers may be given in figures or words (perhaps applying the guidance above to the integer part). If given in figures, they are unspaced (not Platform 9 3⁄4 or Platform 9-3⁄4 but Platform 9+3⁄4 (markup: {{frac|9|3|4}})). In any case the integer and fractional parts should be consistent (not Platform nine and 3⁄4).
  • Metric (SI) measurements generally use decimals, not fractions (5.25 mm, not 51⁄4 mm).
  • Non-metric (imperial and US customary) measurements may use fractions or decimals (51⁄4 inches; 5.25 inches); the practice of reliable sources should be followed, and within-article consistency is desirable.
  • In science and mathematics articles, mixed numbers are rarely used (use ⁠4/3⁠ the original voltage rather than 1⁠1/3⁠ times the original voltage). The use of {{frac}} is discouraged; instead use one of these styles:
    • 1 2 {\displaystyle \textstyle {\frac {1}{2}}} (markup: <math>\textstyle\frac{1}{2}</math>)
    • ⁠1/2⁠ (markup: {{sfrac|1|2}})
    • 1/2 (markup: 1/2)
  • Do not use precomposed fraction characters such as ½ (deprecated markup: &frac12; or &#189;).
  • Ordinal suffixes such as -th should not be used with fractions expressed in figures (not each US state has 1/50th of the Senate's votes; 1/8th mile, but one-fiftieth of the Senate's votes; 1/8 mile; one-eighth mile).
  • For dimensionless ratios (i.e. those without accompanying units), place a colon between integers, or place to between numbers-as-words: favored by a 3:1 ratio or a three-to-one ratio, not a 3/1 ratio or a 3–1 ratio. The same style is used to express odds in sport, gambling, and other statistical predictions.
    • Use a colon (spaced) when one or more decimal points is present (a 3.5 : 1 ratio (markup: a 3.5&nbsp;:&nbsp;1 ratio)).
    • Do not use the colon form where units are involved (dissolve using a 3 ml : 1 g ratio)‍—‌instead see ratios section of table at § Unit names and symbols, below.
See also: Misplaced Pages:Manual of Style/Mathematics § Fractions

Decimals

Shortcut
  • Use a period/full point (.) as the decimal separator, never a comma: 6.57, not 6,57.
  • Numbers between −1 and +1 require a leading zero (0.02, not .02); exceptions are sporting performance averages (.430 batting average) and conventional terms such as .22 caliber.
  • Although repeating digits may be indicated with an overbar (e.g. 14.31{{overline|28}} gives 14.3128), users of screen readers will not hear any indication of the overbar. Apart from in mathematics articles, consider rounding to a reasonable resolution instead (e.g. a half farthing ≈£0.00052 not £0.00052083, an inch ≈0.333 palms not 0.3 palms), or showing initial repeats before the overbar (e.g. 0.333). If overbars are used, consider explaining the notation on first use. Do not write e.g. 14.31(28) because it resembles notation for uncertainty.

Grouping of digits

Shortcut
  • In general, digits should be grouped and separated either by commas or by narrow gaps (never a period/full point).
    • Grouping with commas
      • Left of the decimal point, five or more digits are grouped into threes separated by commas (e.g. 12,200; 255,200 km; 8,274,527th; 1⁄86,400).
      • Numbers with exactly four digits left of the decimal point may optionally be grouped (either 1,250 or 1250), consistently within any given article.
      • Do not use commas to the right of the decimal point, or with numbers not in base 10.
      • Markup: {{formatnum:}} produces this formatting.
    • Grouping with narrow gaps
      • Digits are grouped both sides of the decimal point (e.g. 6543210.123456; 520.01234 °C; ⁠101325/760⁠).
      • Digits are generally grouped into threes. Right of the decimal point, usual practice is to have a final group of four in preference to leaving an "orphaned" digit at the end (99.1234567, but 99.1234567 would also be acceptable). In mathematics-oriented articles long strings may be grouped into fives (e.g. 3.14159265358979323846...).
      • This style is especially recommended for articles related to science, technology, engineering or mathematics, though in these contexts there may be cases in which grouping confuses rather than clarifies. (For example, for fractions written in horizontal format, adding spaces to a fraction like 123456/127 would cause it to be misread as 123⁠456/127⁠ or 1⁠23456/127⁠.)
      • Markup: Templates {{val}} or {{gaps}} may be used to produce this formatting. Note that use of any space character as a separator in numbers, including non-breaking space, is problematic for screen readers. (See § Non-breaking spaces.) Screen readers read out each group of digits as separate numbers (e.g. 30{{thin space}}000 is read as "thirty zero zero zero"). The output of {{val}} and {{gaps}} is compatible with screen readers.
  • Delimiting style should be consistent throughout a given article.
    • Either use commas or narrow gaps, but not both in the same article.
    • Either group the thousands in a four-digit number or do not, but not mixed use in the same article.
    • However, grouping by threes and fives may coexist.
  • Four-digit page numbers and four-digit calendar years should never be grouped (not sailed in 1,492, but dynasty collapsed around 10,400 BC or by 13727 AD, Vega will be the northern pole star).

Percentages

Shortcuts
  • Throughout scientific/​technical articles, and in tables and infoboxes in any article, the symbol % is generally preferred. Omit space (3%, not 3 %), and do not use mixed forms such as three %.
  • The body of non-scientific/​non-technical articles may use either the % symbol or the word(s) percent (American English) or per cent (British English): 10 percent; ten percent; 4.5 per cent.
  • Ranges are written 10–12%, ten to twelve per cent, or ten to twelve percent; not ten–twelve per cent, 10%–12%, or 10 to 12%.
  • When expressing the difference between two percentages, do not confuse a percentage change with a change in percentage points.

Scientific and engineering notation

Shortcuts
  • Scientific notation always has a single nonzero digit to the left of the point: not 60.22×10, but 6.022×10.
  • Engineering notation is similar, but with the exponent adjusted to a multiple of three: 602.2×10.
  • Avoid mixing scientific and engineering notations: A 2.23×10 m region covered by 234.0×10 grains of sand.
  • In a table column (or other presentation) in which all values can be expressed with a single power of 10, consider giving e.g. ×10 once in the column header, and omitting it in the individual entries. (Markup: {{e|7}})
  • In both notations, the number of digits indicates the precision. For example, 5×10 means rounded to the nearest thousand; 5.0×10 to the nearest hundred; 5.00×10 to the nearest ten; and 5.000×10 to the nearest unit.

Markup: {{val}} and {{e}} may be used to format exponential notation.

Uncertainty and rounding

Shortcuts
  • Where explicit uncertainty information (such as a margin of error) is available and appropriate for inclusion, it may be written in various ways:
    • (1.534 ± 0.035) × 10 m
    • 12.34 m ± 5% (not used with scientific notation)
    • 15.34
      −0.23 × 10 m
    • 1.604(48) × 10 J (equivalent to (1.604 ± 0.048) × 10 J)
    • Polls estimated Jones's share of the vote would be 55 percent, give or take about 3 percent
    • Markup: {{+-}}, {{su}}, and {{val}} may be used to format uncertainties.
  • Where explicit uncertainty is unavailable (or is unimportant for the article's purposes), round to an appropriate number of significant digits; the precision presented should usually be conservative. Precise values (often given in sources for formal or matter-of-record reasons) should be used only where stable and appropriate to the context, or significant in themselves for some special reason.
    • The speed of light is defined to be 299,792,458 m/s
    • but Particle velocities eventually reached almost two-thirds the 300-million-metre-per-second speed of light.
    • checks worth $250 (equivalent to $1,800 in 2016) (not $1,845.38 in 2016)
    • The city's 1920 population was 10,000 (not population was 9,996 – an official figure unlikely to be accurate at full precision)
    • but The town was ineligible because its official census figure (9,996) fell short of the statutory minimum of ten thousand (unusual case in which the full-precision official figure is truly informative)
    • The accident killed 337 passengers and crew, and 21 people on the ground (likely that accurate and precise figures were determined)
    • At least 800 persons died in the ensuing mudslides (unlikely that any precise number can be accurate, even if an official figure is issued)
    • or Officials listed 835 deaths, but the Red Cross said dozens more may have gone unreported (in reporting conflicting information, give detail sufficient to make the contrast intelligible)
    • The jury's award was $8.5 million (not $8,462,247.63). The appeals court reduced this to $3,000,001 (one dollar in actual damages, the remainder in punitive damages).
  • The number of decimal places should be consistent within a list or context (The response rates were 41.0 and 47.4 percent, respectively, not 41 and 47.4 percent), unless different precisions are actually intended.
  • It may sometimes be appropriate to note the lack of uncertainty information, especially where such information is normally provided and necessary for full interpretation of the figures supplied.
    • A local newspaper poll predicted 52 percent of the vote would go to Smith, but did not include information on the uncertainty of this estimate
  • The {{undue precision}} template may be added to figures appearing to be overprecise.
  • Avoid using "approximately", "about", and similar terms with figures that have merely been approximated or rounded in a normal and expected way, unless the reader might otherwise be misled.
    • The tallest player was 6 feet 3 inches (not ... about 6 feet 3 inches – heights are conventionally reported only to the nearest inch, even though greater precision may be available in principle)
    • but The witness said the assailant was about 5 feet 8 inches tall ("about" because here the precise value is unknown, with substantial uncertainty)
  • The reader may be assumed to interpret large round numbers (100,000 troops) as approximations. Writing a quantity in words (one hundred thousand troops), especially if the indefinite article (a/an) is used instead of the word one (a hundred thousand troops), can further emphasize its approximate nature.
  • See § Unit conversions below for precision issues when converting units.

Non–base-10 notations

Shortcuts
  • In computer-related articles, use the prefix 0x for hexadecimal and 0b for binary, unless there is a strong reason to use some other notation. Explain these prefixes in the article's introduction or on first use.
  • In all other articles, use {{base}}: 1379, 2013. Markup: {{base|137|9}}, {{base|201|3}}
  • For bases above 10, use symbols conventional for that base (as seen in reliable sources) e.g. for base 16 use 0–9 and A–F.
  • For octal, use 2008. Avoid using a prefix unless it is needed for computer code samples, in which case explain the prefix on first use.

Mathematical formulae

Main page: Misplaced Pages:Manual of Style/Mathematics

There are multiple ways to display mathematical formulae, covered in detail at Misplaced Pages:Manual of Style/Mathematics § Typesetting of mathematical formulae. One uses special MediaWiki <math>...</math> markup using LaTeX syntax, which is capable of complex formulae; the other relies on conventionalized HTML formatting of simple formulae.

The <math> markup is displayed as a PNG image by default. Logged-in users can optionally have it rendered in MathML, or in HTML (via MathJax); detailed instructions are at Help:Displaying a formula.

Do not put <math> markup in headings.

Units of measurement

Shortcuts

Unit choice and order

Quantities are typically expressed using an appropriate "primary unit", displayed first, followed, when appropriate, by a conversion in parentheses e.g. 200 kilometres (120 mi). For details on when and how to provide a conversion, see the section § Unit conversions. The choice of primary units depends on the circumstances, and should respect the principle of strong national ties, where applicable:

  • In non-scientific articles with strong ties to the United States, the primary units are US customary (pounds, miles, feet, inches, etc.)
  • In non-scientific articles with strong ties to the United Kingdom, the primary units for most quantities are metric or other internationally used units, except that:
    • UK engineering-related articles, including those on bridges and tunnels, generally use the system of units in which the subject project was drawn up (but road distances are given in imperial units, with a metric conversion – see next bullet);
    • the primary units for distance/​length, speed and fuel consumption are miles, miles per hour, and miles per imperial gallon (except for short distances or lengths, where miles are too large for practical use);
    • the primary units for personal height and weight are feet​/inches and stones/​pounds;
    • imperial pints are used for quantities of draught beer/​cider and bottled milk;
  • In all other articles, the primary units chosen will be SI units (such as kilograms), non-SI units officially accepted for use with the SI, or such other units as are conventional in reliable sources discussing the article topic (such as revolutions per minute (rpm) for rotational speed, hands for heights of horses, mass and luminosity of the Sun, etc.)
    • the primary SI units for personal height and weight are centimetres and kilograms.

Special considerations:

  • Quantities set via definition (as opposed to measured quantities) should be given first in the units used in the definition, even if this makes the structure of presentation inconsistent: During metrication, the speed limit was changed from 30 mph (48 km/h) to 50 km/h (31 mph).
    • Or use about to emphasize which is the statutory, exact value: ...from 30 mph (about 48 km/h) to 50 km/h (about 31 mph).
  • Nominal quantities (e.g. 2 × 4 lumber) require consideration of whether the article is concerned with the item's actual dimensions or merely with its function. In some cases, the nominal quantity may suffice; in others it may be necessary to give the nominal size (often in non-SI units), the actual size in non-SI units, and the actual size in SI units.
  • Whenever a conversion is given, the converted quantity's value should match the precision of the source (see § Unit conversions).
  • Where the article's primary units differ from the units given in the source, the {{convert}} template's |order=flip flag can be used; this causes the original unit to be shown as secondary in the article, and the converted unit to be shown as primary: {{convert|200|mi|km|order=flip}} → The two cities are 320 kilometres (200 mi) apart.

Unit conversions

See also: Misplaced Pages:WikiProject Astronomy/Manual of Style § Units Shortcuts

Where English-speaking countries use different units for the same quantity, provide a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. But in science-related articles, supplying such conversion is not required unless there is some special reason to do so.

  • Where an imperial unit is not part of the US customary system, or vice versa – and in particular, where those systems give a single term different definitions – a double conversion may be appropriate: Rosie weighed 80 kilograms (180 lb; 12 st 8 lb) (markup: {{convert|80|kg|lb stlb}}); The car had a fuel economy of 5 L/100 km (47 mpg‑US; 56 mpg‑imp) (markup: {{convert|5|L/100km|mpgus mpgimp|abbr=on}}).
  • Generally, conversions to and from metric units and US or imperial units should be provided, except:
    • When inserting a conversion would make a common or linked expression awkward (The four-minute mile).
    • In some topic areas (for example, maritime subjects where nautical miles are the primary units, American football where yards are primary, and articles like Solar System where many interplanetary distances are given) it can be excessive to provide a conversion for every quantity. In such cases consider noting that the article will use a particular unit – possibly giving the conversion factor to other, familiar units in a parenthetical note or a footnote – and link the first occurrence of each unit but not give a conversion every time it occurs. Applying this principle may require editorial discretion; for example, in scientific articles the expected level of reader sophistication should be taken into account.
    • For distances on the scale of between star systems and galaxies, "light-years" or "ly" should be used as primary units, with a conversion to "parsecs" or "pc", but no conversion to SI units. The units should be linked on first mention. For larger quantities, use large number words in prose (million or billion but not thousand) and metric prefixes (kly, Mly, Gly, kpc, Mpc, Gpc) in compact contexts. Examples:
      • First mention in prose: 34.6 ± 2.3 million light-years (10.6 ± 0.705 Mpc)
        • Wikitext: {{convert|34.6|±|2.3|e6ly|Mpc|sigfig=3|lk=on}}
      • Infobox or table: 2.50 Mly (765 kpc)
        • Wikitext: {{cvt|765|kpc|Mly|order=flip|sigfig=3|lk=on}} (use "order=flip" when source uses parsecs)
    • Astronomical units (au) should be converted to kilometers (km) using "million", "billion", or "trillion" in both prose and compact environments like infoboxes and tables. When large interplanetary-scale distances overlap with small interstellar-scale distances, convert au to ly and pc, or ly to pc and au (depending on context). Examples:
      • 49.3 au (7.38 billion km)
        • Wikitext: {{convert|49.3|au|e9km|abbr=unit}}
      • 121,000 astronomical units (1.91 light-years; 0.59 parsecs)
        • Wikitext: {{convert|121000|au|ly pc|abbr=off|lk=on}}
      • 0.9 ly (0.28 pc; 57,000 au)
        • Wikitext: {{convert|0.9|ly|pc au|abbr=unit}}
  • For units of measure that are obsolete, obscure outside of a particular specialty or geography (e.g. furlong, jansky, or rayleigh), or not part of the SI/SI-accepted or US customary systems (e.g. zolotnik), supply a parenthetical conversion into at least SI or SI-accepted units (unless one of the exceptions previously noted applies). Convert each mention, unless this would be excessive given the context. Take care to distinguish between different definitions of the same unit if it has changed over time or differs geographically (e.g. cubit, batman). An approximate or range conversion is acceptable if the exact historical value is uncertain (e.g. stadion).
    • Metric units not part of the SI or accepted for use with it should either be replaced with SI or SI-accepted units (e.g. joules instead of ergs), or they should be treated as obscure units in the same way as furlongs.
  • Metric prefixes used should be commonly known, namely "pico" thru "tera", preferably in commonly-used combinations (e.g. 2,000 kilometers not 2 megameters).
  • Converted quantity values should use a level of precision similar to that of the source quantity value, so the Moon is 380,000 kilometres (240,000 mi) from Earth, not (236,121 mi). Small numbers, especially if approximate, may need to be converted to a range where rounding would cause a significant distortion, so about one mile (1–2 km), not about one mile (2 km). Be careful especially when your source has already converted from the units you're now converting back to. This may be evidenced by multiples of common conversion factors in the data, such as 160 km (from 100 miles). See false precision.
  • {{convert}} and other conversion templates can be used to convert and format many common units, and have options to respect significant figures. To avoid problems with rounding and significant figures, for input to conversion templates use only the original quantity found in reliable sources, not one that a source has already converted. If required by the above rules, the conversion output can be displayed as the primary units with "order=flip". Conversion output can be displayed as the only units with "disp=out"; this retains the original quantity in wikitext for verification by editors.
  • In a direct quotation, always retain the source units. Any conversions can be supplied either in the quote itself (in square brackets, following the original measurement) or in a footnote. See footnoting and citing sources.
  • {{Units attention}} may be added to articles needing general attention regarding choice of units and unit conversions.

Unit names and symbols

"WP:DEGREE" redirects here. For the essay on notability, see WP:POSITION. Shortcuts
Definitions:
  • Examples of unit names: foot, metre, kilometre, (US: meter, kilometer).
  • Examples of unit symbols: ft, m, km.
  • Unit names and symbols should follow the practice of reliable sources.
  • In prose, unit names should be given in full if used only a few times, but symbols may be used when a unit (especially one with a long name) is used repeatedly, after spelling out the first use (e.g. Up to 15 kilograms of filler is used for a batch of 250 kg).
    • Exception: Certain units are generally represented by their symbols (e.g. °C rather than degrees Celsius) even on first use, though their unit names may be used for emphasis or clarity (conversion of degrees Celsius to degrees Fahrenheit).
    • Exception: Consider using inches (but not in.) in place of in where the latter might be misread as a preposition‍—‌but not where the value is followed by a parenthesized conversion e.g. bolts 5 in (12.7 cm) long, or is part of such a conversion (bolts 12.7 cm (5 in) long).
  • Where space is limited, such as in tables, infoboxes, parenthetical notes, and mathematical formulas, unit symbols are preferred.
  • Units unfamiliar to general readers should be presented as a name–symbol pair on first use, linking the unit name (Energies rose from 2.3 megaelectronvolts (MeV) to 6 MeV).
    • Commonly-known SI and SI-accepted units that can be used without linking are: meter (m), gram (g), second (s), ampere (A), liter (L), pascal (Pa), hertz (Hz), degrees Celsius (°C), minute (min), hour (h), day (d), degree (of angle, °), volt (V), watt (W)
  • Ranges use unspaced en dash ({{ndash}}) if only one unit symbol is used at the end (e.g. 5.9–6.3 kg), and spaced en dash ({{snd}}) if two symbols are used (e.g. 3 μm – 1 mm); ranges in prose may be specified using either unit symbol or unit names, and units may be stated either after both numerical values or after the last (all acceptable: from 5.9 to 6.3 kilograms; from 5.9 kilograms to 6.3 kilograms; from 5.9 to 6.3 kg; from 5.9 kg to 6.3 kg).
  • Length–width, length–width–height and similar dimensions may be separated by the multiplication sign (× or &times;) or the word by.
    • The × symbol is preceded by a space (preferably non-breaking), and followed by a space (which may also be non-breaking in short constructions), and each number should be followed by a unit name or symbol:
      • 1 m × 3 m × 6 m, not 1 × 3 × 6 m, (1 × 3 × 6) m, nor 1 × 3 × 6 m
      • a metal plate 1 ft × 3 ft × 0.25 in
      • a railroad easement 10 ft × 2.5 mi
    • With by, the unit need be given only once if it is the same for all dimensions: 1 by 3 by 6 metres or 1 by 3 by 6 m.
    • The unspaced letter x may be used in common terms such as 4x4.
General guidelines on use of units
Aspect Guideline Acceptable Unacceptable
Unit names and symbols Except as listed in the § Specific units table below, unit symbols are uncapi­tal­ized unless they are derived from a proper name, in which case the first letter (of the base unit symbol, not of any prefix) is capitalized. 8 kg
100 kPa
8 Kg
100 kpa
Unit symbols are undotted. 38 cm of rope 38 cm. of rope
Unit names are given in lower case except: where any word would be capital­ized, or where otherwise specified in the SI brochure or this Manual of Style.
  • A gallon is 4 quarts.
  • 4 pascals
  • A Gallon is 4 Quarts.
  • 4 Pascals
  • He walked several miles.
  • Miles of trenches were dug.
The spelling of certain unit names (some of which are listed in § Specific units, below) varies with the variety of English followed by the article.
Write unit names and symbols in upright (roman) type, except where emphasizing in context. 10 m
29 kilograms
10 m
29 kilograms
Thus each two-liter jug contained only two quarts.
Do not use precomposed unit symbol characters. ㎓, ㎦, ㎍, ㎖, ㎉
Numeric values Do not spell out numbers before unit symbols ... 12 min twelve min
... but words or figures may be used with unit names.
  • twelve minutes
  • 12 minutes
Use a non-breaking space ({{nbsp}} or &nbsp;) between a number and a unit symbol, or use {{nowrap}} ... 29 kg (markup: 29&nbsp;kg or {{nowrap|29 kg}}) 29kg
... though with certain symbols no space is used (see "Specific units" table below) ... 23° 47′ 22″ 23 ° 47 ′ 22 ″
... and a normal space is used between a number and a unit name. 29 kilograms
(markup: 29 kilograms)
To form a value and a unit name into a compound adjective use a hyphen or hyphens ...
  • a five-day holiday
  • a five-cubic-foot box
  • a 10-centimeter blade
... but a non-breaking space (never hyphen) separates a value and unit symbol.
  • a blade 10 cm long
a 10-cm blade
Plurals SI unit names are pluralized by adding -s or -es ... 1 ohm; 10 ohms
... except for these irregular forms. 1 henry; 10 henries
1 hertz; 10 hertz
1 lux; 10 lux
1 siemens; 10 siemens
10 henrys
10 hertzes
10 luxes
10 siemenses
Some non-SI units have irregular plurals. 1 foot; 10 feet 10 foots
1 stratum; 10 strata (unusual) 10 stratums
Unit symbols (in any system) are identical in singular and plural.
  • grew from 1 in to 2 in
  • grew from 1 inch to 2 inches
  • grew from one to two inches
grew from 1 in to 2 ins
Powers Format exponents using <sup>, not special characters. km
(markup: km<sup>2</sup>)
km²
(km&#178;)
Or use squared or cubed (after the unit being modified). ten metres per second squared ten metres per squared second
For areas or volumes only, square or cubic may be used (before the unit being modified). ten metres per square second
tons per square mile
sq or cu may be used with US customary or imperial units, but not with SI units. 15 sq mi
3 cu ft
15 sq km
3 cu m
Products Indicate a product of unit names with either a hyphen or a space.
  • foot-pound
  • foot pound
  • footpound
  • foot⋅pound
Indicate a product of unit symbols with &sdot; or &nbsp;.
  • ms = millisecond
  • m⋅s or m s = metre-second
Exception: In some topic areas, such as power engineer­ing, certain products take neither space nor &sdot;. Follow the practice of reliable sources in the article's topic area.
To pluralize a product of unit names, pluralize only the final unit. (Unit symbols are never pluralized.) ten foot-pounds ten feet-pounds
Ratios, rates, densities Indicate a ratio of unit names with per. meter per second meter/second
Indicate a ratio of unit symbols with a forward slash (/), followed by either a single symbol or a parenthesized product of symbols – do not use multiple slashes. Or use , , etc.
  • metre per second
  • m/s
  • m⋅s
  • mps
  • kg/(m⋅s)
  • kg⋅m⋅s
  • kg/m⋅s
  • kg/m/s
To pluralize a ratio of unit names, pluralize only the numerator unit. (Unit symbols are never pluralized.)
  • ten newton-metres per second
  • 10 N⋅m/s
Some of the special forms used in the imperial and US customary systems are shown here ...
  • mph = miles per hour
  • mpg = miles per gallon
  • psi = pounds per square inch
... but only the slash or negative exponent notations are used with SI (and other metric) units.
  • g/m
  • g⋅m
gsm
  • km/h
  • km⋅h
kph
Prefixes Prefixes should not be separated by a space or hyphen. kilopascal
  • kilo pascal
  • kilo-pascal
Prefixes are added without contraction, except as shown here: kilohm
megohm
hectare
kiloohm
megaohm
hectoare
The deci-, deca-, and hecto- prefixes should generally be avoided; exceptions include decibel, hectolitre, hectare, and hectopascal.
  • 100 metres
  • 0.1 km
1 hectometre
Do not use M for 10, MM for 10, or B for 10 (except as noted elsewhere on this page for M and B, e.g. for monetary values) 3 km
8 MW
125 GeV
3 Mm
8 MMW
125 BeV
Mixed units Mixed units are traditionally used with the imperial and US customary systems ...
  • a wall 1 ft 1 in thick
  • a wall 1 foot 1 inch thick
  • a man 6 feet 2 inches tall
  • a 6-foot 2-inch man
  • a 6 ft 2 in man
  • 1 ft , 1 in (no comma)
  • 1 foot , 1 inch
  • a man 6 foot 2 tall
  • a 6-foot 2 man
  •  
  • 1 US fl pt 8 oz
  • 1 US fl pt 8 US fl oz
... and in expressing time durations ...
  • 1:30:07
  • 1:30 
  • 1 h 30 min 7 s
  • 01 30 07 
  • 1:30′07″
  • 1:30′
  • 1 hr 30 min 7 sec
  • 1 h 30 m 7 s
... but are not used with metric units.
  • 1.33 m
  • 133 cm
1 m 33 cm

Note to table:

  1. Use this format only where it is clear from context whether it means hours and minutes (HH:MM) or minutes and seconds (MM:SS).
  2. This format is used in astronomy (see the IAU Style Manual for details).

Specific units

Shortcuts
  • The following table lists only units that need special attention.
  • The SI Brochure should be consulted for guidance on use of other SI and non-SI units.
Guidelines on specific units
Group Unit name Unit symbol Comment
Length, speed
  • inch
  • foot
  • in
  • ft
Do not use &prime; (′), &Prime; (″), apostrophe ('), or quote ("). Exception: in music, eight-foot pitch notation describes organ stops and wind instrument lengths in feet. A prime may be used with an explanation on first use, e.g. a 16 foot (16′) organ pedal stop; see MOS:MUSIC.
foot per second ft/s (not fps)
hand h or hh Equal to 4 inches; used in measurement of horses. A dot may be followed by additional inches e.g. 16.2 hh indicates 16 hands 2 inches.
  • kn (not kt, Kt, or kN)
  • KIAS or kn
  • KCAS
  • KEAS
  • KTAS
  • kn (not KGS)
Used in aviation contexts for aircraft and wind speeds, and also used in some nautical and general meteorological contexts. When applied to aircraft speeds, kn means KIAS unless stated otherwise; if kn is used for calibrated airspeed, equivalent airspeed, true airspeed, or groundspeed, explicitly state and link to, upon first use, the type of speed being referred to (for instance, kn equivalent airspeed, or, if severely short of space, kn EAS); for airspeeds other than indicated airspeed, the use of the specific abbreviation for the type of airspeed being referred to (such as KEAS) is preferred. When referring to indicated airspeed, either kn or KIAS is permissible. Groundspeeds and wind speeds must use the abbreviation kn only.
  • metre
  • meter (US)
m
micron μm (not μ) Markup: &mu;m  Link to micrometre (for which micron is a synonym) on first use.
astronomical unit au
(not A.U., ua)
The preferred form is au. Articles that already use AU may switch to au or continue with AU; seek consensus on the talk page.
  • mile
  • miles per hour
  • nautical mile
  • mi
  • mph
  • nmi or NM (not nm or M)
In nautical and aeronautical contexts where there is risk of confusion with nautical miles, consider writing out references to statute miles as e.g. 5 statute miles rather than simply 5 miles.
Volume, flow
  • cubic centimetre
  • cubic centimeter (US)
cm Markup: cm<sup>3</sup>
cc Non-SI abbreviation used for certain engine displacements. Link to Cubic centimetre on first use.
  • imperial fluid ounce
  • imperial pint
  • imperial quart
  • imperial gallon
  • US fluid ounce
  • US dry pint
  • US liquid pint
  • US dry quart
  • US liquid quart
  • US gallon
  • imp fl oz
  • imp pt
  • imp qt
  • imp gal
  • US fl oz
  • US dry pt
  • US liq pt
  • US dry qt
  • US liq qt
  • US gal
  • US or imperial (or imp) must be specified for all these units.
  • fluid or fl must be specified for fluid ounces (to avoid ambiguity versus avoirdupois ounce and troy ounce).
  • For US pints and quarts, dry or liquid (liq) are needed to be fully unambiguous, though context determines whether or not to repeat those qualifiers on every use in a given article.
cubic foot cu ft (not cf) Write five million cubic feet, 5,000,000 cu ft, or 5×10 cu ft, not 5 MCF.
cubic foot per second cu ft/s (not cfs)
  • litre
  • liter (US)
L (not l or ℓ) The symbol l (lowercase "el") in isolation (i.e. outside forms as ml) is easily mistaken for the digit 1 or the capital letter I ("eye") and should not be used.
  • millilitre
  • milliliter (US)
ml or mL Derivative units of the litre may use l (lowercase "el").
Mass, weight, force, density, pressure
  • gram
  • kilogram
  • g
  • kg
Not gramme, kilogramme
  • long ton
  • short ton
Spell out in full.
t (not mt, MT, or Mt)
pound per square inch psi
  • troy ounce
  • troy pound
  • oz t
  • lb t
The qualifier t or troy must be specified where applicable. Use the qualifier avdp (avoirdupois) only where there is risk of confusion with troy ounce, imperial fluid ounce, US fluid ounce, or troy pound; but articles about precious metals, black powder, and gemstones should always specify which type of ounce (avoirdupois or troy) is being used, noting that these materials are normally measured in troy ounces and grams.
  • avoirdupois ounce
  • avoirdupois pound
  • oz or oz avdp
  • lb or lb avdp
carat carat Used to express masses of gemstones and pearls.
Purity carat or karat k or Kt (not kt or K) A measure of purity for gold alloys. (Do not confuse with the unit of mass with the same spelling.)
Time
  • second
  • minute
  • hour
  • s
  • min
  • h
Do not use &prime; (′), &Prime; (″), apostrophe (') or quote (") for minutes or seconds. See also the hours–minutes–seconds formats for time durations described in the Unit names and symbols table.
year a Use a only with an SI prefix multiplier (a rock formation 540 Ma old, not Life expectancy rose to 60 a).
y or yr See § Long periods of time for all affected units.
Information, data bit bit (not b or B) See also § Quantities of bytes and bits, below. Do not confuse bit/second or byte/second with baud (Bd).
byte B or byte (not b or o)
bit per second bit/s (not bps, b/s)
byte per second B/s or byte/s (not Bps, bps, b/s)
Angle
arcminute Markup: {{prime}}  (prime ′ not apostrophe/​single quote '). No space (47′, not 47 ′).
arcsecond Markup: {{pprime}}  (double prime ″ not double-quote "). No space (22″, not 22 ″).
degree ° Markup: degree ° not masculine ordinal º or ring  ̊. No space (23°, not 23 °).
Temperature degree Fahrenheit °F (not F) Markup: 12{{nbsp}}°C, not 12°C or 12°{{nbsp}}C . Do not use the precomposed characters U+2103 ℃ DEGREE CELSIUS or U+2109 ℉ DEGREE FAHRENHEIT.
degree Rankine °R (not R)
degree Celsius (not degree centigrade) °C (not C)
kelvin (not degree kelvin) K (not °K) Use a non-breaking space: 12{{nbsp}}K (use the normal Latin letter K, not U+212A K KELVIN SIGN). When writing out the unit (not usually necessary), pluralize, e.g. 12 kelvins (see Kelvin#Orthography)
Energy cal In certain subject areas, calorie is convention­ally used alone; articles following this practice should specify on first use whether the use refers to the small calorie or to the kilocalorie (large calorie). Providing conversions to SI units (usually calories to joules or kilocalories to kilojoules) may also be useful. A kilocalorie (kcal) is 1000 calories. A calorie (small calorie) is the amount of energy required to heat 1 gram of water by 1 °C. A kilocalorie is also a kilogram calorie.
  • kilocalorie
  • large calorie
  • kilogram calorie
  • (not Calorie – can be ambiguous)
kcal

Quantities of bytes and bits

Shortcut

In quantities of bits and bytes, the prefixes kilo- (symbol k or K), mega- (M), giga- (G), tera- (T), etc., are ambiguous in general usage. The meaning may be based on a decimal system (like the standard SI prefixes), meaning 10, 10, 10, 10, etc., or it may be based on a binary system, meaning 2, 2, 2, 2, etc. The binary meanings are more commonly used in relation to solid-state memory (such as RAM), while the decimal meanings are more common for data transmission rates, disk storage and in theoretical calculations in modern academic textbooks.

Prefixes for decimal and binary multiples
Decimal
Value SI
1000 10 k kilo
1000 10 M mega
1000 10 G giga
1000 10 T tera
1000 10 P peta
1000 10 E exa
1000 10 Z zetta
1000 10 Y yotta
1000 10 R ronna
1000 10 Q quetta
Binary
Value IEC JEDEC
1024 2 Ki kibi K kilo
1024 2 Mi mebi M mega
1024 2 Gi gibi G giga
1024 2 Ti tebi T tera
1024 2 Pi pebi
1024 2 Ei exbi
1024 2 Zi zebi
1024 2 Yi yobi

Follow these recommendations when using these prefixes in Misplaced Pages articles:

  • Following the SI standard, a lower-case k should be used for "kilo-" whenever it means 1000 in computing contexts, whereas a capital K should be used instead to indicate the binary prefix for 1024 according to JEDEC. If, under the exceptions detailed further below, the article otherwise uses IEC prefixes for binary units, use Ki instead.
  • Do not assume that the binary or decimal meaning of prefixes will be obvious to everyone. Explicitly specify the meaning of k and K as well as the primary meaning of M, G, T, etc. in an article ({{BDprefix}} is a convenient helper). Consistency within each article is desirable, but the need for consistency may be balanced with other considerations.
  • The definition most relevant to the article should be chosen as primary for that article, e.g. specify a binary definition in an article on RAM, decimal definition in an article on hard drives, bit rates, and a binary definition for Windows file sizes, despite files usually being stored on hard drives.
  • Where consistency is not possible, specify wherever there is a deviation from the primary definition.
  • Disambiguation should be shown in bytes or bits, with clear indication of whether in binary or decimal base. There is no preference in the way to indicate the number of bytes and bits, but the notation style should be consistent within an article. Acceptable examples include:
    • A 64 MB (64 × 1024-byte) video card and a 100 GB (100 × 1000-byte) hard drive
    • A 64 MB (64 × 2-byte) video card and a 100 GB (100 × 10-byte) hard drive
    • A 64 MB (67,108,864-byte) video card and a 100 GB (100,000,000,000-byte) hard drive
  • Avoid combinations with inconsistent form such as A 64 MB (67,108,864-byte) video card and a 100 GB (100 × 1000-byte) hard drive. Footnotes, such as those seen in Power Macintosh 5500, may be used for disambiguation.
  • Unless explicitly stated otherwise, one byte is eight bits (see Byte § History).
  • ShortcutThe IEC prefixes kibi- (symbol Ki), mebi- (Mi), gibi- (Gi), etc., are generally not to be used except:
    • when the majority of cited sources on the article topic use IEC prefixes;
    • in a direct quote using the IEC prefixes;
    • when explicitly discussing the IEC prefixes; or
    • in articles in which both types of prefix are used with neither clearly primary, or in which converting all quantities to one or the other type would be misleading or lose necessary precision, or declaring the actual meaning of a unit on each use would be impractical.

Currencies and monetary values

Shortcuts "WP:MONEY" and "WP:CURRENCY" redirect here. For the WikiProject focusing on articles about currencies, see Misplaced Pages:WikiProject Numismatics. "WP:$" and "WP:£" redirect here. For the policy on paid editing, see Misplaced Pages:Paid-contribution disclosure. For the humor page, see Help:Buying Misplaced Pages.

Choice of currency

  • In country-specific articles, such as Economy of Australia, use the currency of the subject country.
  • In non-country-specific articles, such as Wealth, use US dollars (US$123 on first use, generally $123 thereafter), euros (€123), or pounds sterling (£123).

Currency names

  • Do not capitalize the names or denominations of currencies, currency subdivisions, coins and banknotes: not a Five-Dollar bill, four Quarters, and one Penny total six Dollars one Cent but a five-dollar bill, four quarters, and one penny total six dollars one cent. Exception: where otherwise required, as at the start of a sentence or in such forms as Australian dollar.
  • To pluralize euro, use the standard English plurals (ten euros and fifty cents), not the invariant plurals used for European Union legislation and banknotes (ten euro and fifty cent). For the adjectival form, use a hyphenated singular (a two-euro pen and a ten-cent coin).
  • Link the first occurrence of lesser-known currencies (e.g. Mongolian tögrögs).

Currency symbols

  • In general, the first mention of a particular currency should use its full, unambiguous signifier (e.g. A$52), with subsequent references using just the appropriate symbol (e.g. $88), unless this would be unclear. Exceptions:
    • In an article referring to multiple currencies represented by the same symbol (e.g. the dollars of the US, Canada, Australia, New Zealand, and other countries – see Currency symbols § dollar variants) use the full signifier (e.g. US$ or A$, but not e.g. $US123 or $123 (US)) each time, except (possibly) where a particular context makes this both unnecessary and undesirable.
    • In articles entirely on US-related topics, all occurrences of the US dollar may be shortened ($34), unless this would be unclear.
    • For currencies that use a unit named the "pound":
      • Use the £ symbol (U+00A3 £ POUND SIGN) for unambiguous referrals to sterling, the United Kingdom's currency. Avoid the U+20A4 ₤ LIRA SIGN.
      • GBP, sterling's ISO 4217 code, should be used to disambiguate that currency from others. Avoid using stg. or GB£.
      • For currencies other than sterling, use the symbol or abbreviation conventionally employed for that currency, if any.
  • Link the first occurrence of lesser-known currency symbols (e.g. )
  • If there is no common English abbreviation or symbol, follow the ISO 4217 standard. See also List of circulating currencies.
See also: Misplaced Pages:Manual of Style/Abbreviations § Unicode abbreviation ligatures

Currency formatting

  • A point (full stop or period, .) – never a comma – is used as the decimal marker ($6.57, not $6,57).
  • For the grouping of digits (e.g. £1,234,567) see § Grouping of digits, above.
  • Do not place a currency symbol after the accompanying numeric figures (e.g. 123$, 123£, 123€) unless that is the normal convention for that symbol when writing in English: smaller British coins include 1p, 2p, and 5p denominations.
  • Currency abbreviations preceding a numeric value are unspaced if they consist of a nonalphabetic symbol alone (£123 or €123), or end with a nonalphabetic symbol (R$123); but spaced (using {{nbsp}}) if completely alphabetic (R 123 or JOD 123).
  • Ranges should be expressed giving the currency signifier just once: $250–300, not $250–$300.
  • million and billion should be spelled out on first use, and (optionally) abbreviated M or bn (both unspaced) thereafter: She received £70 million and her son £10M; the school's share was $250–300 million, and the charity's $400–450M.
  • In general, a currency symbol should be accompanied by a numeric amount e.g. not He converted his US$ to A$ but He converted his US dollars to Australian dollars or He exchanged the US$100 note for Australian dollars.
    • Exceptions may occur in tables and infoboxes where space is limited e.g. Currencies accepted: US$, SFr, £, . It may be appropriate to wikilink such uses, or add an explanatory note.

Currency conversions

  • Conversions of lesser-known currencies may be provided in terms of more familiar currencies – such as the US dollar, euro or pound sterling – using an appropriate rate (which is often not the current exchange rate). Conversions should be in parentheses after the original currency, along with the convert-to year; e.g. the grant in 2001 was 10,000,000 Swedish kronor ($1.4M, €970,000, or £850,000 as of 2009)
  • For obsolete currencies, provide an equivalent (formatted as a conversion) if possible, in the modern replacement currency (e.g. euros for amounts denominated in francs), or a US-dollar equivalent where there is no modern equivalent.
  • In some cases, it may be appropriate to provide a conversion accounting for inflation or deflation over time. See {{Inflation}} and {{Inflation-fn}}.
  • When converting among currencies or inflating/deflating, it is rarely appropriate to give the converted amount to more than three significant figures; typically, only two significant figures are justified: the grant in 2001 was 10,000,000 Swedish kronor ($1.4M, €970,000, or £850,000), not ($1,390,570, €971,673 or £848,646)

Common mathematical symbols

Shortcuts See also: Misplaced Pages:Manual of Style/Mathematics, Misplaced Pages:Manual of Style § Common mathematical symbols, and Help:Displaying a formula
  • The Insert menu below the editing window gives a more complete list of math symbols, and allows symbols to be inserted without the HTML encoding (e.g. &divide;) shown here.
  • Spaces are placed to left and right when a symbol is used with two operands (the sum 4 + 5), but no space is used when there is one operand (the value +5). Exception: spaces are usually omitted in inline fractions formed with /: 3/4 not 3 / 4.
  • The {{mvar}} (for single-letter variables) and {{math}} (for more complicated expressions) templates are available to display mathematical formulas in a manner distinct from surrounding text.
  • The {{nbsp}} and {{nowrap}} templates may be used to prevent awkward linebreaks.
Common mathematical symbols
Symbol name Example Markup Comments
Plus /
positive
x + y {{math|''x'' + ''y''}}
+y {{math|+''y''}}
Minus /
negative
xy {{math|''x'' &minus; ''y''}} Do not use hyphens (-) or dashes ({{ndash}} or {{mdash}}).
y {{math|&minus;''y''}}
Plus-minus /
minus-plus
41.5 ± 0.3 41.5 &plusmn; 0.3
−(±a) = ∓a {{math|1=&minus;(&plusmn;''a'') = &#8723;''a''}}
Multiplication,
dot
xy {{math|''x'' &sdot; ''y''}} Do not use the letter x to indicate multiplication. However, an unspaced x may be used as a substitute for "by" in common terms such as 4x4.
Multiplication,
cross
x × y {{math|''x'' &times; ''y''}}
Division, obelus x ÷ y {{math|''x'' &divide; ''y''}}
Equal / equals x = y {{math|1=''x'' = ''y''}} or
{{math|''x'' {{=}} ''y''}}
Note the use of 1= or {{=}} to make the template parameters work correctly
Not equal xy {{math|''x'' &ne; ''y''}}
Approx. equal π ≈ 3.14 {{math|''&pi;'' &asymp; 3.14}}
Less than x < y {{math|''x'' &lt; ''y''}}
Less or equal xy {{math|''x'' &le; ''y''}}
Greater than x > y {{math|''x'' &gt; ''y''}}
Greater or equal xy {{math|''x'' &ge; ''y''}}

Geographical coordinates

Shortcuts
For draft guidance on, and examples of, coordinates for linear features, see Misplaced Pages:WikiProject Geographical coordinates/Linear.
Quick guide:
Quick how-to

To add 57°18′22″N 4°27′32″W / 57.30611°N 4.45889°W / 57.30611; -4.45889 to the top of an article, use {{Coord}}, thus:

{{Coord|57|18|22|N|4|27|32|W|display=title}}

These coordinates are in degrees, minutes, and seconds of arc.

"title" means that the coordinates will be displayed next to the article's title at the top of the page (in desktop view only; title coordinates do not display in mobile view) and before any other text or images. It also records the coordinates as the primary location of the page's subject in Misplaced Pages's geosearch API.

To add 44°06′45″N 87°54′47″W / 44.1124°N 87.9130°W / 44.1124; -87.9130 to the top of an article, use either

{{Coord|44.1124|N|87.9130|W|display=title}}

(which does not require minutes or seconds but does require the user to specify north/ south and east/west) or

{{Coord|44.1124|-87.9130|display=title}}

(in which the north and east are presumed by positive values while the south and west are negative ones). These coordinates are in decimal degrees.

  • Degrees, minutes and seconds, when used, must each be separated by a pipe ("|").
  • Map datum must be WGS84 if possible (except for off-Earth bodies).
  • Avoid excessive precision (0.0001° is <11 m, 1″ is <31 m).
  • Maintain consistency of decimal places or minutes/seconds between latitude and longitude.
  • Latitude (N/S) must appear before longitude (E/W).

Optional coordinate parameters follow the longitude and are separated by an underscore ("_"):

Other optional parameters are separated by a pipe ("|"):

  • display
    |display=inline (the default) to display in the body of the article only,
    |display=title to display at the top of the article only (in desktop view only; title coordinates do not display in mobile view), or
    |display=inline,title to display in both places.
  • name
    name=X to label the place on maps (default is PAGENAME)

Thus: {{Coord|44.1172|-87.9135|dim:30_region:US-WI_type:event

|display=inline,title|name=accident site}}

Use |display=title (or |display=inline,title) once per article, for the subject of the article, where appropriate.

Geographical coordinates on Earth should be entered using a template to standardise the format and to provide a link to maps of the coordinates. As long as the templates are adhered to, a robot performs the functions automatically.

First, obtain the coordinates. Avoid excessive precision.

The {{Coord}} template offers users a choice of display format through user styles, emits a Geo microformat, and is recognised (in the title position) by the "nearby" feature of Misplaced Pages's mobile apps and by external service providers such as Google Maps and Google Earth, and Yahoo. Infoboxes automatically emit {{Coord}}.

The following formats are available.

  • For degrees only (including decimal values): {{coord|dd|N/S|dd|E/W}}
  • For degrees/minutes: {{coord|dd|mm|N/S|dd|mm|E/W}}
  • For degrees/minutes/seconds: {{coord|dd|mm|ss|N/S|dd|mm|ss|E/W}}

where:

  • dd, mm, ss are the degrees, minutes and seconds, respectively;
  • N/S is either N for northern or S for southern latitudes;
  • E/W is either E for eastern or W for western longitudes;
  • negative values may be used in lieu of S and W to denote Southern and Western Hemispheres

For example:

For the city of Oslo, located at 59° 54′ 50″ N, 10° 45′ 8″ E:

{{coord|59|54|50|N|10|45|08|E}} – which becomes 59°54′50″N 10°45′08″E / 59.91389°N 10.75222°E / 59.91389; 10.75222

For a country, like Botswana, with no source on an exact geographic center, less precision is appropriate due to uncertainty:

{{coord|22|S|24|E}} – which becomes 22°S 24°E / 22°S 24°E / -22; 24

Higher levels of precision are obtained by using seconds:

{{coord|33|56|24|N|118|24|00|W}} – which becomes 33°56′24″N 118°24′00″W / 33.94000°N 118.40000°W / 33.94000; -118.40000

Coordinates can be entered as decimal values:

{{coord|33.94|S|118.40|W}} – which becomes 33°56′S 118°24′W / 33.94°S 118.40°W / -33.94; -118.40

Increasing or decreasing the number of decimal places controls the precision. Trailing zeros may be added as needed to give both values the same appearance.

Heathrow Airport, Amsterdam, Jan Mayen and Mount Baker are examples of articles that contain geographical coordinates.

Generally, the larger the object being mapped, the less precise the coordinates should be. For example, if just giving the location of a city, precision greater than degrees (°), minutes (′), seconds (″) is not needed, which suffice to locate, for example, the central administrative building. Specific buildings or other objects of similar size would justify precisions down to 10 meters or even one meter in some cases (1″ ~15 m to 30 m, 0.0001° ~5.6 m to 10 m).

The final field, following the E/W, is available for attributes such as type:, region:, or scale: (the codes are documented at Template:Coord/doc § Coordinate parameters).

When adding coordinates, please remove the {{coord missing}} tag from the article, if present (often at the top or bottom).

For more information, see the geographical coordinates WikiProject.

Templates other than {{coord}} should use the following variable names for coordinates: lat_d, lat_m, lat_s, lat_NS, long_d, long_m, long_s, long_EW.

See also

Notes

  1. See Arbitration Committee statements of principles in cases on style-related edit warring in June 2005, November 2005, and February 2006; and Misplaced Pages:General sanctions/Units in the United Kingdom.
  2. See also this July 2022 RfC.
  3. ^ For use in tables, infoboxes, references, etc. Only certain citation styles use abbreviated date formats. By default, Misplaced Pages does not abbreviate dates. Use a consistent citation style within any one article.
  4. All-numeric yyyy-mm-dd dates might be assumed to follow the ISO 8601 standard, which mandates the Gregorian calendar. Also, technically all years must have (only) four digits, but Misplaced Pages is unlikely to need to format a date beyond the year 9999 anytime soon.
  5. The routine linking of dates is deprecated. This change was made August 24, 2008, on the basis of this archived discussion. It was ratified in two December 2008 RfCs: Misplaced Pages:Manual of Style/Dates and numbers/Three proposals for change to MOSNUM and Misplaced Pages:Manual of Style/Dates and numbers/Date Linking RFC.
  6. For consensus discussion on abbreviated date formats like "Sep 2", see Misplaced Pages talk:Manual of Style/Archive 151 § RFC: Month abbreviations
  7. These formats cannot, in general, be distinguished on sight, because there are usages in which 05-03-1991 represents March 5, and other usages in which it represents May 3. According to a prehistoric discussion of Misplaced Pages date formats:

    Some years ago an American student I knew at university went into a panic when she received a note informing her that her exams were scheduled to start on 03-05-1991. She went into a severe weekend of cramming (studying for 18+ hours per day), until she was almost hospitalised from exhaustion. Only then did she realise that her exams didn't start on the 5th of March – two weeks from the date she got the notice – but the 3rd of May.

    In contrast, there is no common usage in which 1991-05-03 represents anything other than May 3.

  8. ^ Body in this context means the main prose of the article, as distinguished from reference citations, tabular data, infoboxes, navigation templates, and metadata such as hatnote templates, etc. Other parts of the Manual of Style may use body to mean 'the bulk of the article after the lead section', but that is not the meaning here. Misplaced Pages's article leads are not written in a different prose style from the material following them.
  9. The calendar practices of Oxford Dictionary of National Biography and Encyclopædia Britannica can be inferred by looking up the birth and death dates of famous, well-documented individuals.
  10. A change from a preference for two digits, to a preference for four digits, on the right side of year–year ranges was implemented in July 2016 per this RFC.
  11. Some precomposed fractions may not work with screen readers, and not all fractions are available precomposed.
  12. These three characters are in ISO/IEC 8859-1 and work in screen readers.
  13. The number in parentheses in a construction like 1.604(48) × 10 J is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.
  14. The prefixes 0x for hexadecimal and 0b for binary have widespread support in systems programming languages including C, C++, Python, Rust and Swift.
  15. One such situation is with Unicode codepoints, which use U+; U+26A7, not 0x26A7.
  16. If there is disagreement about the primary units used in a UK-related article, discuss the matter on the article talk-page or at Misplaced Pages talk:Manual of Style/Dates and numbers (WT:MOSNUM). If consensus cannot be reached, refer to historically stable versions of the article and retain the units used in these as the primary units. Also note the style guides of British publications (e.g. The Times, under "Metric").
  17. These definitions are consistent with all units of measure mentioned in the SI Brochure and with all units of measure catalogued in EU directive 80/181/EEC.
  18. Misplaced Pages follows common practice regarding bytes and other data traditionally quantified using binary prefixes (e.g. mega- and kilo-, meaning 2 and 2 respectively) and their unit symbols (e.g. MB and KB) for RAM and decimal prefixes for most other uses. Despite the IEC's 1998 international standard creating several new binary prefixes (e.g. mebi-, kibi-, etc.) to distinguish the meaning of the decimal SI prefixes (e.g. mega- and kilo-, meaning 10 and 10 respectively) from the binary ones, and the subsequent incorporation of these IEC prefixes into the IEC 80000-13, consensus on Misplaced Pages in computing-related contexts favours the retention of the more familiar but ambiguous units KB, MB, GB, TB, PB, EB, etc. over use of unambiguous IEC binary prefixes. For detailed discussion, see WT:Manual of Style (dates and numbers)/Archive/Complete rewrite of Units of Measurements (June 2008).
  19. Whether 00A3 is displayed with one or two bars is typeface (font) dependent.
  20. See also this February 2023 RfC.

References

  1. Garraty, John A.; Carnes, Mark C., eds. (1999). "Editorial note". American National Biography. Oxford University Press. pp. xxi–xxii.
  2. Coordinated Universal Time (UTC) (PDF). Bureau International des Poids et Mesures. June 2, 2009. p. 3. CCTF/09-32. Retrieved October 5, 2022. This coordination began on January 1, 1960, and the resulting time scale began to be called informally 'Coordinated Universal Time.' 
  3. "Fundamental Physical Constants: Standard Uncertainty and Relative Standard Uncertainty". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 25, 2015. Retrieved December 12, 2017.
  4. ^ "Chapter 4: Non-SI units that are accepted for use with the SI". SI Brochure: The International System of Units (SI) (PDF) (9th ed.). Bureau International des Poids et Mesures. 2019. Retrieved 2020-09-24. Table 8, p 145, gives additional guidance on non-SI units.
  5. "Council Directive of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement". Eur-Lex.Europa.eu. European Union. 2017 . 80/181/EEC (Document 01980L0181-20090527). Retrieved December 12, 2017.
  6. Wilkins, G. A. (1989). "5.14 Time and angle". IAU Style Manual (PDF). International Astronomical Union. p. S23. Retrieved 12 December 2017.
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