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 Wikipedia article titles, see theNaming conventions (numbers and dates) guideline.
Where this manual gives options, maintain consistency within an article unless there is a good reason to do otherwise. TheArbitration 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.[a] 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.
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 [bracketed interpolation], article text, or footnotes.
Except on pages that are inherently time-sensitive and updated regularly (e.g.the "Current events" portal), terms such asnow,today,currently,present,to date,so far,soon,upcoming,ongoing, andrecently should usually be avoided in favor of phrases such asduring the 2010s,since 2010, andin August 2020. Wording can usually be modified to remove the "now" perspective: notshe is the current director butshe became director on 1 January 2025; not2010–present butbeginning in 2010 orsince 2010. Terms likely to go out of date includebest known for,holds the record for, etc.[b] For current and future events, use phrases such asas of March 2025 orsince the beginning of 2025 to signal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, butonly recently developed state legislatures.
Dates, years, and other chronological items should be linked only when they are relevant to the subjectand likely to be useful to a reader; this rule does not apply to articles that are explicitly on a chronological item, e.g.2002,19th century(as discussed atWikipedia:Linking § Chronological items).[e]
Dates in article body text[h] should all use the same format:She fell ill on25 June 2005 and died on28 June, notShe fell ill on25 June 2005 and died onJune 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 thecitation style being used (but all-numeric date formats other thanyyyy-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):
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.
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 particularEnglish-speaking country, the choice of date format...
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 particularEnglish-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 particularEnglish-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".
Use either the BC–AD or the BCE–CE notation consistently within the same article. Exception: do not changedirect 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 (applyingWikipedia:Manual of Style § Retaining existing styles) by opening a discussion under a heading using the wordera, 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 (5BC, not5BC). It is advisable to use anon-breaking space.
AD appears before or after a year (AD106,106AD); BCE, CE, and BC always appearafter (106CE,3700BCE,3700BC).
In general, omit CE or AD, except to avoid ambiguity or awkwardness.
Typically, writeTheNorman Conquest took place in 1066 not1066CE orAD1066.
ButPlotinus lived at the end of the 3rd century AD (not simplyat 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 orborn January 15, 22 CE, notborn in 2 norJanuary 15, 22).
Ranges beginning in BC / BCE should specify the ending era: write450 to 200 BCE or450 BC to 200 BC or450 BCE to 200 CE, but not450 BCE to 200. (seeRanges)
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 –[3250BCE calibrated], or at least indicate the date type –[uncalibrated]. 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 January1, 1950.) Write3000 yearsBP or3000YBP or3000years before present but not forms such as3000 before present and3000 years before the present. If one of the abbreviated forms is used, link toBefore Present on first use:The Jones artifact was dated to 4000YBP, 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 in221AH (836 CE), orin 836 AD (221AH).
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 inyear−67. (The expressions−67 and68BCE refer to the same year.)
A date can be given in any appropriate calendar, as long as it is (at the minimum) given in theJulian calendar or theGregorian calendar or both, as described below. For example, an article on the earlyhistory of Islam may give dates in bothIslamic 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 before 15October 1582 (when the Gregorian calendar was first adopted in some places) are normally given in the Julian calendar.
Dates after 4October1582 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 1January even if a different start-of-year date was observed in the place being discussed.
Dates for Roman history before 45BC are given in theRoman 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.
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 toCategory:Articles containing ambiguous dates for further attention.
If an article contains Julian calendar dates after 4 October 1582 (as in theOctober 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.
A simpleyear–year range is written using anen dash (–,– or{{ndash}}, or{{nbnd}} for a non-breaking en dash), not an em dash, hyphen, or slash; this dash isunspaced (that is, with no space on either side); and the end year is usually given in full:
Although non-abbreviated years are generallypreferred,two-digit ending years (1881–82, but never1881–882 or1881–2)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.[j] 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 where the first digits change (1899–1900, not1899–00) or for years from the first millennium (886–887, not886–87).
Theslash 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 anunspaced en dash as well:
day–day:5–7January 1979;January5–7, 1979;elections were held March 5–8.
month–month:the 1940 peak period was May–July;the peak period was May–July1940; (butthe peak period wasMay 1940 – July 1940 uses aspaced en dash;see below)
In certain cases where at least one item on either side of the en dash contains a space, then aspaced en dash ({{snd}}) is used. For example:
between specific dates in different months:They travelledJune 3 – August18, 1952;They travelled 3 June – 18August 1952
between dates in different years:
Charles Robert Darwin (12February1809 – 19 April 1882) was an English naturalist...
Abraham Lincoln (February12, 1809 – April15, 1865) was the 16th president of...
between months in different years:The exception was in force August1892 – January 1903;The Ghent Incursion (March 1822 – January1, 1823) was ended by the New Year's Treaty
if the modifierapplies to only one of the two endpoints of the range, use aspaced en dash:150 BCE – 50 BCE,5 BC – 12 AD,c. 1393 – 1414
if the modifierapplies 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 asfrom orbetween, but not both:from 1881 to 1886 (notfrom 1881–1886);between June1 and July3 (notbetween June1 – July3)
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. Thus1982–present (as of 2025) – if writing in 2025 – is preferable to1982–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 isSince 1982.
In tables and infoboxes where space is limited,pres. may be used (1982–pres.). Do not use incomplete-looking constructions such as1982– and1982–... .
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 aperson still living:Serena Williams (born September26, 1981) is a..., not(September26, 1981 – ) or(born on September26, 1981).
Do not use* to indicateborn; useb. only where space is limited, e.g., in tables and infoboxes; use eitherborn orb. consistently in any given table column.
Wherebirthdate is unknown:John Smith (died May1, 1622) orJohn Smith (died 1622)
Do not use† to indicatedied; used. only where space is limited, with consistency within any given table column.
Anovernight period may be expressed using a slash between two contiguous dates:the night raids of 30/31May 1942 orraids of 31May/ 1June 1942.
Or use an en dash: (unspaced)raids of 30–31May 1942; (spaced)raids of31May – 1June 1942.
The{{Age}} template can keep ages current in infoboxes and so on:
To indicate "around", "approximately", or "about", the use of the{{circa}} template is preferred at first occurrence over justc. At later occurrences,c. is preferred overcirca,c,ca,ca.,around,approximately, orapprox.:
Where birth/death limits have been inferred from known dates of activity:
Offa of Mercia (before 734 – 26July 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.,[[Floruit|fl.]], or{{fl.}} may be used:
The corresponding template{{r.}} produces reign output:r. 540–562, though it is often clearer to write outreigned 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 aregnal orAH 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:April14, 1224 (unattested date). Do not use a question mark (1291?), because it fails to communicate the nature of the uncertainty.
Wherec. or a similar form appearswhich applies only to one of the two endpoints of the range, use a spaced en dash ({{snd}}).
Where a modifierapplies to the range as a whole, such asfl. andr., use a spaced or unspaced en dash as appropriate to the range if this modifier is disregarded.
Some modifiers, such astraditionally,around,BH, andCE, 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 andtraditionally 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 hasBCE applying only to one endpoint, but the range is ambiguous. Consider using400–200 BCE,400 BCE – 200 BCE, or400 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 asc.,fl.,r.,b., andd.
Context determines whether the12- or24-hour clock is used. In all cases, colons separate hours, minutes, and (where present) seconds, e.g.1:38:09pm or13:38:09. Use figures (11a.m. or12:45p.m.) rather than words (twelve forty-five p.m.).
12-hour clock times end with lower-casea.m. orp.m., oram orpm, preceded by anon-breaking space, e.g.2:30p.m. or2:30pm (markup:2:30{{nbsp}}p.m. or2:30{{nbsp}}pm), not2:30p.m. or2:30pm. Hours should not have a leading zero (e.g.2:30p.m., not02:30p.m.). Usually, usenoon andmidnight rather than12 pm and12 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, thena.m. orp.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 not1530). Hours under 10 should have a leading zero (08:15). The time00:00 refers to midnight at the start of a date,12:00 to noon, and24:00 to midnight at the end of a date, but24 should not be used for the first hour of the next day (e.g. use00:10 for ten minutes after midnight, not24:10).
Give dates and times appropriate to thetime zone where an event took place. For example, the date of theattack on Pearl Harbor should be December7, 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 inCoordinated Universal Time (UTC). For example:
Rarely, the time zone in which an event took place has since changed; for example, China until 1949 was divided intofive 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;[2]Universal Time (UT) is the appropriate term for the mean time at theprime 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.
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 onlywet anddry seasons. Unambiguous alternatives includeearly1995;the second quarter of 1995;March to June1995;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 (2018Winter Olympics;Arab Spring) that is capitalized under theguidelines 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 ofInterzone orthe summer 1985 issue ofInterzone).
To refer to a decade as a chronological periodper se (not with reference to a social era or cultural phenomenon), always use four digits and ans, as inthe1980s. Do not usethe1980's, orthe1980‑ies.
Prefixes should be hyphenated (themid‑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:theRoaring'20s;theGay'90s;condemning the '60s counterculture—butgrew up in 1960s Boston, moving to Dallas in1971. Do not write:the90's;the90s; orthe90s'.
Another alternative (where seen in reliable sources) is to spell the decade out, capitalized:changing attitudes of the Sixties.
The sequence of numbered years in dates runs...2BC, 1BC, 1AD, 2AD...; there is no "year zero".
Treat the 1st century AD as years1–100, the 17th century as1601–1700, and the second millennium as1001–2000; similarly, the 1st century BC / BCE was100–1 BC / BCE, the 17th century BC / BCE was1700–1601 BC / BCE, and the second millennium2000–1001 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 or19th-century painting). Do not use superscripts (19th century).
Do not capitalize (the best Nineteenth-century paintings;during the Nineteenth Century).
When the term is frequent, combineyr(years) orya(years ago) withk(thousand):kya,kyr;M(million):Mya,Myr; andb(short-scale billion):bya,byr.(SeeYear § Abbreviations yr and ya for more information.)
In academic contexts,annus-based units are often used with anSI prefix:ka(kiloannus),Ma(megaannus), andGa(gigaannus).(SeeYear § SI prefix multipliers for more information.)
Show the meaning parenthetically, and consider linking to the appropriate section of theYear article(Year § Abbreviations yr and ya orYear § SI prefix multipliers) on first occurrence and where the use is a standalone topic of interest. In source quotations, use square brackets:"a potassium-argon date of 35.1Mya [million years ago]..."
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 nineexpressible in one or two words may be expressed either in numerals or in words (16 orsixteen,84 oreighty-four,200 ortwo 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 andfifty-six thousand, butfivehundred andfivethousand.
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 notthree < 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 notthe first three primes are two, three, and five; butzero-sum game androots of unity).
Sport scores and vote tallies should be given as numerical figures (a25–7 victory;passed with 7 ayes, 2 nays, and 1 abstention, thoughpassed 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 orages were5, 7, and32, but notages werefive, 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 indifferent formats:twelve 90-minute volumes or12 ninety-minute volumes, not12 90-minute volumes ortwelve ninety-minute volumes.
Avoid awkward juxtapositions:On February 25, 2011, twenty-one more were chosen, notOn 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), whileEvery locker except1 was searched implies that locker number1 was the only locker not searched.
Only figures are used with unitsymbols (12 min nottwelve min); but figures or words may be used with unitnames (12 minutes ortwelve minutes), subject to the provisions above.
Other numbers
Other numbers are given in numerals (3.75,544) or in forms such as21million (orbillion,trillion, etc. – but rarelythousand orhundred). Markup:21{{nbsp}}million
Billion andtrillion are understood to represent theirshort-scale values of 109(1,000,000,000) and 1012(1,000,000,000,000), respectively. Keep this in mind when translating articles from non-English or older sources. Use of the long scale was normal before the nineteenth century, when the US changed to the short scale. The UK government changed to the short scale in 1974, and the long scale continues to be used in most other European languages; seehistory of long and short scales.
M (unspaced, capitalized) orbn (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 £61million was split among her husband (£1M), her son (£5M), her butler (£10M), and her three Weimaraners (£15M each).).
SI prefixes and symbols, such asmega-(M),giga-(G) andtera-(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 1.3Gpeople, 300megadeaths would be expected.
When it is done anyway, for contextually important reasons, link the first spelled-out instance of each quantity (e.g.[[crore]], 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, writethreecrore (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.
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.
"MOS:1ST" redirects here. For the guideline on the first sentence in articles, seeMOS: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 usefirst throughninth, not1st through9th, for single-digit ordinals.
In "suffix" forms, use two-letter suffixes:1st, 2nd, 3rd, 4th and so on (2ndBattalion not2dBattalion). Do not superscript (e.g.123rd).
In English text, do not use a dot (.) or theordinal indicator (º). The masculineº or feminineª ordinal indicator is acceptable in names, quotations, etc. from languages that conventionally use it. An Italian example:313º Gruppo Addestramento Acrobatico not313º Acrobatic Training Group orthe 313º. Use HTML markup for languages that do not have a special character but conventionally use a superscript, like2e in French.
Regnal numbers are normally written with ASCIIRoman numerals (without suffix, e.g.Elizabeth II notElizabeth IInd,Elizabeth 2nd orElizabeth Ⅱ).
Likedate ranges, number ranges and page ranges should state the full value of both the beginning and end of the range, separated by anen dash:pp.1902–1911 orentries342–349. Except within quotations, avoid abbreviated forms such as1902–11 or342–9, which are not understood universally, are sometimes ambiguous, and can cause inconsistent metadata to be created in citations.
Nouns followingsimple fractions are singular (took1⁄4 dose;net change was −1⁄2 point;3⁄2 dose).
Nouns followingmixed 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;365.25days;paid 5 dollars per work hour, 1 dollar per travel hour, 0 dollars per standby hour;increased by 1point butnet change +1points;net change −1points;net change 1.0points).
The same rules apply to numbers given in words (one dose;one and one-half doses;zero dollars;net change of negative one points).
Where numerator and denominator can each be expressed in one word, a fraction is usuallyspelled out (e.g.a two-thirds majority;moved one-quarter mile); use figures if a fraction appears with a unit symbol (e.g.1⁄4mi (markup:{{frac|1|4}} mi), nota quarter of a mi orone-quarter mi). A common exception is a series of values:The distances were1+1⁄4,2⁄3 and1⁄2 mile, respectively.
Mixed numbers may be given in figures or words (perhaps applying the guidanceabove to the integer part). If given in figures, they are unspaced (notPlatform 93⁄4 orPlatform 9-3⁄4 butPlatform9+3⁄4 (markup:{{frac|9|3|4}})). In any case the integer and fractional parts should be consistent (notPlatform nine and3⁄4).
Metric (SI) measurements generally use decimals, not fractions (5.25mm, not51⁄4mm).
Non-metric (imperial and US customary) measurements may use fractions or decimals (51⁄4inches;5.25inches); the practice of reliable sources should be followed, and within-article consistency is desirable.
In science and mathematics articles, mixed numbers are rarely used (use4/3 the original voltage rather than11/3 times the original voltage). The use of{{frac}}is discouraged; instead use one of these styles:
For other fractions, where templates cannot be used due to technical limitations, use the ASCII representation with spaces. For example,Category:4 ft 10 7/8 in gauge railways.
Ordinal suffixes such as-th should not be used with fractions expressed in figures (noteach US state has 1/50th of theSenate's votes;1/8th mile, butone-fiftieth of theSenate's votes;1/8 mile;one-eighth mile).
For dimensionless ratios (i.e. those without accompanying units), place a colon between integers, or placeto between numbers-as-words:favored by a 3:1 ratio ora three-to-one ratio, nota 3/1 ratio ora 3–1 ratio. The same style is used to expressodds 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 : 1 ratio)).
Do not use the colon form where units are involved (dissolve using a3 ml : 1 g ratio)—instead seeratios section of table at§Unit names and symbols, below.
Use a period/full point (.) as thedecimal separator,never a comma:6.57, not6,57.
Numbers between −1 and +1 require a leading zero (0.02, not.02); exceptions are sporting performance averages (.430batting average) and conventional terms such as.22caliber.
Although repeating digits may be indicated with anoverbar (e.g.14.31{{overline|28}} gives14.3128), 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. ahalf farthing≈£0.00052 not£0.00052083, aninch≈0.333palms not0.3palms), 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 resemblesnotation for uncertainty.
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, but99.1234567 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 ofany space character as a separator in numbers, including non-breaking space, is problematic forscreen readers.(See§ Non-breaking spaces.) Screen readers read out eachgroup 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 (notsailed in 1,492, butdynasty collapsed around 10,400BC orby13727 AD, Vega will be the northern pole star).
Throughout scientific/technical articles, and in tables and infoboxes inany article, the symbol% is generally preferred. Omit space (3%, not3%), and do not use mixed forms such asthree%.
The body[h] of non-scientific/non-technical articles may use either the% symbol or the word(s)percent (American English) orpercent (British English):10 percent;ten percent;4.5 per cent.
Ranges are written10–12%,ten to twelve per cent, orten to twelve percent; notten–twelve per cent,10%–12%, or10 to 12%.
When expressing the difference between two percentages, do not confuse a percentage change with a change inpercentage points.
Scientific notation always has a single nonzero digit to the left of the point: not60.22×1022, but6.022×1023.
Engineering notation is similar, but with the exponent adjusted to a multiple of three:602.2×1021.
Avoid mixing scientific and engineering notations:A2.23×102 m2 region covered by234.0×106 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.×107 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,5×103 means rounded to the nearest thousand;5.0×103 to the nearest hundred;5.00×103 to the nearest ten; and5.000×103 to the nearest unit.
Markup:{{val}} and{{e}} may be used to format exponential notation.
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 explicituncertainty is unavailable (or is unimportant for the article's purposes), round to an appropriate number ofsignificant 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 299,792,458m/s
butParticle 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 (notpopulation was 9,996 – an official figure unlikely to be accurate at full precision)
butThe 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 $8.5million (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, not41 and 47.4 percent), unless different precisions are actually intended.
It may sometimes be appropriate to note thelack 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)
butThe 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 theindefinite article (a/an) is used instead of the wordone (a hundred thousand troops), can further emphasize its approximate nature.
In computer-related articles, use the prefix0x for hexadecimal and0b for binary,[n] unless there is a strong reason to use some other notation.[o] 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}}
Forbases above 10, use symbols conventional for that base (as seen in reliable sources) e.g. forbase 16 use0–9 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.
The<math> markup is displayed as aPNG image by default. Logged-in users can optionally have it rendered inMathML, or in HTML (viaMathJax); detailed instructions are atHelp:Displaying a formula.
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 ofstrong national ties, where applicable:
Innon-scientific articles with strong ties to the United States, the primary units areUS customary (pounds,miles, feet, inches, etc.)
Innon-scientific articles with strong ties to the United Kingdom, the primary units for most quantities are metric or other internationally used units,[p] except that:
UK engineering-related articles, including those on bridges and tunnels, generally use the system of units in which the subject project wasdrawn 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 aremiles, 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;
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 30mph (48km/h) to 50km/h (31mph).
Or useabout to emphasize which is the statutory, exact value:...from 30mph (about 48km/h) to 50km/h (about 31mph).
Nominal quantities (e.g.2×4lumber) 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 theoriginal unit to be shown as secondary in the article, and theconverted unit to be shown as primary:{{convert|200|mi|km|order=flip}} →The two cities are 320 kilometres (200 mi) apart.
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 animperial unit is not part of theUS 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 whereyards are primary, and articles likeSolar 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 betweenstar systems andgalaxies, "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, uselarge 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 millionlight-years (10.6 ± 0.705 Mpc)
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:
For units of measure that are obsolete, obscure outside of a particular specialty or geography (e.g.furlong,jansky, orrayleigh), 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 ofergs), 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 alevel of precision similar to that of the source quantity value, sothe Moon is 380,000kilometres (240,000mi) from Earth, not(236,121mi). Small numbers, especially if approximate, may need to be converted to a range where rounding would cause a significant distortion, soabout one mile (1–2km), notabout one mile (2km). 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).Seefalse precision.
{{convert}} and otherconversion 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 adirect 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.Seefootnoting andciting sources.
{{Units attention}} may be added to articles needing general attention regarding choice of units and unit conversions.
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 250kg).
Exception: Certain units are generally represented by their symbols (e.g.°C rather thandegrees 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 usinginches (but notin.) in place ofin where the latter might be misread as a preposition—but not where the value is followed by a parenthesized conversion e.g.bolts 5in (12.7cm) long, or is part of such a conversion (bolts 12.7cm (5in) long).
Units unfamiliar to general readers should be presented as a name–symbol pair on first use, linking the unit name (Energies rose from 2.3megaelectronvolts (MeV) to 6MeV).
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.5.9–6.3kg), and spaced en dash ({{snd}}) if two symbols are used (e.g.3μm – 1mm); 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 6.3kg;from 5.9kg to 6.3kg).
Length–width, length–width–height and similar dimensions may be separated by the multiplication sign (× or×) or the wordby.
The× symbol, orby, 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 is typically followed by a unit name or symbol:
1 m × 3 m × 6 m, but not(1 × 3 × 6) m or1 × 3 × 6 m3
a metal plate 1 ft × 3 ft × 0.25 in
a railroad easement 10 ft × 2.5 mi
Optionally, the unit may be given just once if it's the same for all dimensions:1 by 3 by 6 metres;1 by 3 by 6 m;1 × 3 × 6 metres;1 × 3 × 6 m
The letterx, unspaced, may be used in common terms such as4x4.
General guidelines on use of units
Aspect
Guideline
Acceptable
Unacceptable
Unit names and symbols
Except as listed in the§ Specific units table below, unitsymbols 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.[q]
8 kg 100 kPa
8 Kg 100 kpa
Unit symbols are undotted.
38 cm of rope
38 cm. of rope
Unitnames are given in lower case except: where any word would be capitalized, or where otherwise specified in the SI brochure[4] or this Manual of Style.
Unitsymbols (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.
km2 (markup:km<sup>2</sup>)
km² (km²)
Or usesquared orcubed (after the unit being modified).
ten metres per second squared
ten metres per squared second
For areas or volumes only,square orcubic may be used (before the unit being modified).
ten metres per square second
tons per square mile
sq orcu may be used with US customary or imperial units, but not withSI units.
15sqmi 3cuft
15sqkm 3cum
Products
Indicate a product of unitnames with either a hyphen or a space.
foot-pound
foot pound
footpound
foot⋅pound
Indicate a product of unitsymbols with⋅ or .
ms = millisecond
m⋅s orms = metre-second
Exception: In some topic areas, such as power engineering, certain products take neither space nor⋅. Follow the practice of reliable sources in the article's topic area.
To pluralize a product of unitnames, pluralize only the final unit. (Unitsymbols are never pluralized.)
ten foot-pounds
ten feet-pounds
Ratios, rates, densities
Indicate a ratio of unitnames withper.
meter per second
meter/second
Indicate a ratio of unitsymbols with a forward slash (/), followed by either a single symbol or a parenthesized product of symbols – do not use multiple slashes. Or use−1,−2, etc.
metre per second
m/s
m⋅s−1
mps
kg/(m⋅s)
kg⋅m−1⋅s−1
kg/m⋅s
kg/m/s
To pluralize a ratio of unitnames, pluralize only the numerator unit. (Unitsymbols 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...
The following table lists only units that need special attention.
TheSI Brochure[4] 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′(′),″(″), 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.a16 foot (16′) organ pedal stop; seeMOS:MUSIC.
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 meansKIAS unless stated otherwise; ifkn 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,knequivalent airspeed, or, if severely short of space,knEAS); for airspeeds other than indicated airspeed, the use of the specific abbreviation for the type of airspeed being referred to (such asKEAS) is preferred. When referring to indicated airspeed, eitherkn orKIAS is permissible. Groundspeeds and wind speedsmust use the abbreviationkn only.
metre
meter(US)
m
micron
μm (notμ)
Markup:μm Link tomicrometre (for which micron is a synonym) on first use.
In nautical and aeronautical contexts where there is risk of confusion with nautical miles, consider writing out references tostatute miles as e.g.5statutemiles rather than simply5miles.
For US pints and quarts,dry orliquid (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 (notcf)
Writefive million cubic feet,5,000,000cuft, or5×106 cu ft, not5MCF.
cubic foot per second
cu ft/s (notcfs)
litre
liter(US)
L(notl orℓ)
The symbol l (lowercase "el") in isolation (i.e. outside forms as ml) is easily mistaken for the digit1 or the capitalletter I ("eye") and should not be used.
millilitre
milliliter(US)
ml ormL
Derivative units of the litre may use l (lowercase "el").
The qualifiert ortroy 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 ortroy) is being used, noting that these materials are normally measured in troy ounces and grams.
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′(′),″(″), apostrophe(') or quote(") for minutes or seconds. See also the hours–minutes–seconds formats for time durations described in theUnit names and symbols table.
year
a
Usea only with anSI prefix multiplier (a rock formation 540Maold, notLife expectancy rose to 60a).
Use a non-breaking space:12{{nbsp}}K (usethe normal Latin letter K, notU+212AKKELVIN SIGN). When writing out the unit (not usually necessary), pluralize, e.g.12 kelvins (seeKelvin#Orthography)
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 toSI 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.
In quantities ofbits andbytes, the prefixeskilo- (symbolk orK),mega- (M),giga- (G),tera- (T), etc., are ambiguous in general usage. The meaning may be based on a decimal system (like the standardSI prefixes), meaning 103, 106, 109, 1012, etc., or it may be based on a binary system, meaning 210, 220, 230, 240, etc. The binary meanings are more commonly used in relation to solid-state memory (such asRAM), while the decimal meanings are more common for data transmission rates, disk storage and in theoretical calculations in modern academic textbooks.
Follow these recommendations when using these prefixes in Wikipedia articles:
Following the SI standard, a lower-casek should be used for "kilo-" whenever it means 1000 in computing contexts, whereas a capitalK 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, useKi 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 onhard 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 64MB (64×10242-byte) video card and a 100GB(100×10003-byte) hard drive
A 64MB (64×220-byte) video card and a 100GB(100×109-byte) hard drive
A 64MB(67,108,864-byte) video card and a 100GB(100,000,000,000-byte) hard drive
Avoid combinations with inconsistent form such asA 64MB(67,108,864-byte) video card and a 100GB(100×10003-byte) hard drive. Footnotes, such as those seen inPower Macintosh 5500, may be used for disambiguation.
Unless explicitly stated otherwise, one byte is eight bits (seeByte § History).
TheIEC prefixeskibi- (symbolKi),mebi- (Mi),gibi- (Gi), etc., are generally not to be used except:[r]
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.
Incountry-specific articles, such asEconomy of Australia, use the currency of the subject country.
Innon-country-specific articles, such asWealth, 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: nota Five-Dollar bill, four Quarters, and one Penny total six Dollars one Cent buta 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 asAustralian dollar.
To pluralizeeuro, use the standard English plurals (ten euros and fifty cents), not theinvariant 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.$88), unless this would be unclear.Exceptions:
In an article referring to multiple currencies represented by the same symbol (e.g. the dollars of the US, Canada, Australia, New Zealand, and other countries –seeCurrency symbols § dollar variants) use the full signifier (e.g.US$ orA$, but not e.g.$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 theUS dollar may be shortened ($34), unless this would be unclear.
Do not place a currency symbolafter the accompanying numeric figures (e.g.123$,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 areunspaced if they consist of a nonalphabetic symbol alone (£123 or€123), or end with a nonalphabetic symbol (R$123); butspaced (using{{nbsp}}) if completely alphabetic (R 123 orJOD 123).
Ranges should be expressed giving the currency signifier just once:$250–300, not$250–$300.
million andbillion should be spelled out on first use, and (optionally) abbreviatedM orbn (both unspaced) thereafter:She received £70 million and her son £10M;the school's share was$250–300 million, and the charity's $400–450M.
In general, a currency symbol should be accompanied by a numeric amount e.g. notHe converted hisUS$ toA$ butHe converted his US dollars to Australian dollars orHe exchanged theUS$100 note for Australian dollars.
Exceptions may occur in tables and infoboxes where space is limited e.g.Currencies accepted:US$,SFr,£,€. It may be appropriate to wikilink such uses, or add an explanatory note.
Currency conversions
Conversions oflesser-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 oftennot 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 10,000,000Swedish kronor ($1.4M, €970,000, or £850,000 as of 2009[update])
Forobsolete currencies, provide an equivalent (formatted as a conversion) if possible, in the modern replacement currency (e.g. euros for amounts denominated infrancs), 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 10,000,000Swedish kronor ($1.4M, €970,000, or £850,000), not($1,390,570, €971,673 or £848,646)
TheInsert 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.÷) shown here.
Spaces are placed to left and right when a symbol is usedwith two operands (the sum 4 + 5), but no space is used whenthere is one operand (the value+5).Exception: spaces are usually omitted in inline fractions formed with/:3/4 not3 / 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.
"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 Wikipedia's geosearch API.
Use|display=title (or|display=inline,title) once per article, for the subject of the article, where appropriate.
PerWP:ORDER, the template is placed at the bottom of the article in the 'end matter', after anynavigation templates, but before allcategories, including the{{DEFAULTSORT}} template. The{{coord}} template may also be placed within aninfobox, instead of at the bottom of the article.
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.
The{{Coord}} template offers users a choice of display format throughuser styles, emits aGeo microformat, and is recognised (in thetitle position) by the "nearby" feature of Wikipedia'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 eitherN for northern orS for southernlatitudes;
E/W is eitherE for eastern orW for westernlongitudes;
negative values may be used in lieu ofS andW to denote Southern and WesternHemispheres
For example:
For the city ofOslo, located at 59° 54′ 50″ N, 10° 45′ 8″ E:
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.
Generally, the larger the object being mapped, theless 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 10meters or even one meter in some cases (1″ ~15m to 30m, 0.0001° ~5.6m to 10m).
^All-numericyyyy-mm-dd dates might be assumed to follow theISO 8601 standard, which mandates the Gregorian calendar. Also, technically all years must have (only) four digits, but Wikipedia is unlikely to need to format a date beyond the year 9999 anytime soon.
^These formats cannot, in general, be distinguished on sight, because there are usages in which05-03-1991 represents March5, and other usages in which it represents May3. According toa prehistoric discussion of Wikipedia 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 which1991-05-03 represents anything other than May3.
^abBody 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 usebody to mean 'the bulk of the article after the lead section', but that is not the meaning here. Wikipedia's article leads are not written in a different prose style from the material following them.
^The calendar practices ofOxford Dictionary of National Biography andEncyclopædia Britannica can be inferred by looking up the birth and death dates of famous, well-documented individuals.
^A change from a preference for two digits, to a preference for four digits, on the right side ofyear–year ranges was implemented in July 2016 perthis RFC.
^Some precomposed fractions may not work with screen readers, and not all fractions are available precomposed.
^These three characters are inISO/IEC 8859-1 and work in screen readers.
^The number in parentheses in a construction like1.604(48) × 10−4 J is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.[3]
^The prefixes0x for hexadecimal and0b for binary have widespread support in systems programming languages includingC,C++,Python,Rust andSwift.
^One such situation is withUnicode codepoints, which useU+;U+26A7, not0x26A7.
^If there is disagreement about the primary units used in a UK-related article, discuss the matter on the article talk-page or atWikipedia 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 thestyle guides of British publications (e.g.The Times, under "Metric").
^These definitions are consistent with all units of measure mentioned in theSI Brochure[4] and with all units of measure catalogued inEU directive 80/181/EEC.[5]
^Wikipedia follows common practice regardingbytes and other data traditionally quantified usingbinary prefixes (e.g.mega- andkilo-, meaning 220 and 210 respectively) and their unit symbols (e.g.MB andKB) for RAM anddecimal 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 decimalSI prefixes (e.g.mega- andkilo-, meaning 106 and 103 respectively) from the binary ones, and the subsequent incorporation of these IEC prefixes into theIEC 80000-13, consensus on Wikipedia in computing-related contexts favours the retention of the more familiar but ambiguous unitsKB,MB,GB,TB,PB,EB, etc. over use of unambiguous IEC binary prefixes.For detailed discussion, seeWT:Manual of Style (dates and numbers)/Archive/Complete rewrite of Units of Measurements (June 2008).
^Whether 00A3 is displayed with one or two bars is typeface (font) dependent.
Unacceptable
Corrected