See more Wikipedia:Manual of Style/Dates and numbers articles on AOD.

Powered by
Share this page on
Article provided by Wikipedia

( => ( => ( => Wikipedia:Manual of Style/Dates and numbers [pageid] => 183692 ) =>

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.

Where this manual provides options, consistency should be maintained 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, and that revert-warring over optional styles is unacceptable.[1] If discussion cannot determine which style to use in an article, defer to the style used by the first major contributor.

General notes[edit]

Quotations, titles, etc.[edit]

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 [bracketed interpolation], article text, or footnotes.

Non-breaking spaces[edit]

Guidance on the use of "non-breaking spaces ("hard spaces") –  , {{"nbsp}},  , {{"thinsp}} – is given in some sections below; {{"nowrap}} may also be useful in controlling linebreaks in some situations. Not all situations in which hard spaces or {{"nowrap}} may be appropriate are described. For further information see "Wikipedia:Manual of Style § Non-breaking spaces and "Wikipedia:Line-break handling.

Chronological items[edit]

Statements likely to become outdated[edit]


Except on pages updated regularly (e.g. "the "Current events" portal), terms such as now, currently, to date, so far, soon, and recently should usually be avoided in favor of phrases such as during the 1990s, since 2010, and in August 1969. For current and future events, use phrases like as of November 2017 or since the beginning of 2017 to signal the time-dependence of the information. Using {{"as of|2017}} will produce the text As of 2017 , with the additional benefit of putting the article in a category flagging it for periodic review. A full date is specified with {{as of|2017|11|19}}. However, do not replace since the beginning of 2005 with {{as of|2005}} because some information (the beginning of 2005) would be lost; instead, make use of the template's alternate-text parameter: {{"as of|2005|alt=since the beginning of 2005}}.

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.

Times of day[edit]


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 (12:45 p.m.) rather than words (twelve forty-five p.m.).

Time zones

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 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 "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 a historical event took place has since changed; for example, China to 1949 was divided into "five time zones, whereas all of modern China is "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 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.

Dates, months and years[edit]


These requirements do not apply to dates in quotations or titles; see "Wikipedia:Manual of Style § Quotations. Special rules apply to citations; see "Wikipedia:Citing sources § Citation style.


Acceptable date formats
General use Only where brevity is helpful
(refs,[3] tables, infoboxes, etc.)
2 September 2001 2 Sep 2001
September 2, 2001 Sep 2, 2001 A comma follows the year unless followed by other punctuation:[4]
  • The weather on March 12, 2005, was clear and warm
  • Everyone remembers July 21, 1969 – when man 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 2001-08-02 Use yyyy-mm-dd format only with "Gregorian dates from 1583 onward.[5]
September 2001 Sep 2001

Unacceptable date formats (except in external titles and quotes)
Unacceptable Acceptable Comments
Sep. 2 Sep 2 Do not add a dot to the day or to an abbreviated month[7]
9. June 9 June or June 9
9 june
june 9
Months are capitalized
9th June
June 9th
the 9th of June
Do not use ordinals (1st, 2nd, 3rd, etc.)
09 June
June 09
Do not use a leading zero in month or day ...
2007-4-15 2007-04-15 ... except in all-numeric (yyyy-mm-dd) format
2007/04/15 Do not use any separator other than the hyphen
07-04-15 Do not abbreviate year to two digits
Do not use dd-mm-yyyy, mm-dd-yyyy or yyyy-dd-mm formats.[8]
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
May 1 or 1 May
June 0622 June 622 Do not zero-pad years
sold in the year 1995 sold in 1995 Use "in the year" only where needed for clarity (About 1800 ships arrived in the year 1801)

  • 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, or
  • the format expected in the "citation style being used (however, 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)
  • the format used for publication dates in the article;
  • the format expected in the citation style adopted in the article (e.g. 20 Sep 2008); 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[edit]
Retaining existing format[edit]

Era style[edit]


Julian and Gregorian calendars[edit]


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.

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).

At some places and times, the new year began on a date other than 1 January. For example, in England and its colonies until 1752, the year began on "Annunciation Day, 25 March; see the "New Year article for other styles. In writing about historical events, however, years should be assumed to have begun on 1 January (see the example of the execution of Charles I in ""Differences in the start of the year"); if there is reason to use another start-of-year date, this should be noted.

If there is a need to mention "Old or New Style dates in an article (as in the "Glorious Revolution), 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).


  •   1881–1886;  1881–1992 (not 1881–86;  1881 – 1992)
Markup: 1881{{"ndash}}1886 or 1881–1886
  • 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.
  • 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.
  • 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)
  • 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 February 1809 – 19 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 – January 1, 1823
Do not use * to indicate born; use b. only where space is limited e.g. tables and infoboxes; use either born or b. consistently in any given table column.
Do not use to indicate died; use d. only where space is limited, with consistency within any given table column.
Or use an en dash: (unspaced) raids of 30–31 May 1942;  (spaced) raids of 31 May – 1 June 1942.
  •  {{age|1989|7|23}} returns: 28
  •  {{age|1989|7|23}}-year-old returns: 28-year-old
  •  {{age|1989|7|23}} years old returns: 28 years old

Uncertain, incomplete, or approximate dates[edit]

  •   At the birth of Roger Bacon (c. 1214) ...
  •   John Sayer (c. 1750 – 2 October 1818) ...
  •   the Igehalkid dynasty of Elam, c. 1400 BC ...
  •   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) ...)
  •   Offa of Mercia (before 734 – 26 July 796) ...
  •   Robert Menli Lyon (1789 – after 1863) ...
  •   Ambrose Gwinnett Bierce (June 24, 1842 – after December 26, 1913) ...
  •   Jacobus Flori ("fl. 1571–1588) ...
The 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.
  •   Anne Smith (born 1912 or 1913; died 2013) ...


Days of the week[edit]


Unambiguous alternatives include early 1995;  the first quarter of 1995;  January to March 1995;  spent the southern summer in Antarctica.


  • Prefixes should be hyphenated (the mid‑1980s;  pre‑1960s social attitudes).
  • 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 (the Roaring '20s,  the Gay '90s,  condemning the '60s counterculture, but grew up in 1960s Boston, moving to Dallas in 1971, and do not write the 90's;  the 90s;  or the 90s').
  • A third alternative (where seen in reliable sources) is to spell the decade out, capitalized: changing attitudes of the Sixties

Centuries and millennia[edit]


Long periods of time[edit]


Numbers as figures or words[edit]


See also information on specific situations, elsewhere in this guideline.

Generally, in article text:


Notes and exceptions:



Number ranges[edit]

As with date ranges (see above), number ranges in general, such as page ranges, should state the full value of both for the beginning and end of the range, with an en dash between, e.g. pp. 1902–1911,  entries 342–349. Forms such as 1901–11 and 342–9 may be used where space is limited (such as in tables and infoboxes), or where a "citation style formally requires it. (As usual, quotations are not changed.)

Singular versus plural[edit]

Fractions and ratios[edit]

  •    – markup: <"math>\textstyle\frac{1}{2}</math>
  •   1/2 – markup: {{"sfrac|1|2}}
  •   1/2 – markup: 1/2



Grouping of digits

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,  186,400).
  • Numbers with exactly four digits left of the decimal point may optionally be grouped (either  1,250  or  1250), provided that this is consistent within each article.
  • 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).
  • 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.
  • Markup: Templates {{"val}} or {{"gaps}} may be used to produce this formatting. Note that use of any space character 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&thinsp;000  is read as "thirty zero zero zero".)
  • 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.



Scientific and engineering notation[edit]

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

Uncertainty and rounding [edit]

  •  (1.534 ± 0.035) × 1023 m
  •  12.34 m2 ± 5% (not used with scientific notation)
  •  15.34 +0.43
× 1023 m
  •  1.604(48) × 10−4 J (equivalent to (1.604 ± 0.048) × 10−4 J)[9]
  •  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.
  •   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 three airport workers (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).
  •   A local newspaper poll predicted 52 percent of the vote would go to Smith, but did not publish information on the uncertainty of this estimate
  •   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)

Non-"base-10 notations[edit]


Units of measurement[edit]


Unit choice and order[edit]

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:

Special considerations:

Unit conversions[edit]


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. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so.

Unit names and symbols[edit]

  • Examples of unit names: foot, meter, kilometer.
  • Examples of unit symbols: ft, m, km.
  • 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 (automatic 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).
General guidelines on unit names and symbols
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.[12] 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[13] or this Manual of Style.["clarification needed]
  • He walked several miles.
  • Miles of trenches were dug.
A Gallon equals 4 Quarts.
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.
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
Values with no accompanying unit are usually given in figures. Set the pointer to 5. Set the pointer to five.
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}})
... 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 the appropriate -s or -es suffix ... 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
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. km2
(markup: km<sup>2</sup>)
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 &"middot; or &"nbsp; (Note: {{"middot}} is not equivalent to &middot;.)
  • ms = millisecond
  • m·s or m s = metre-second
Exception: In some topic areas, such as power engineer­ing, certain products take neither space nor &middot;. 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
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 −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 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/m2
  • g·m−2
  • km/h
  • km·h−1
Prefixes Prefixes should not be separated by a space or hyphen. 25 kilopascals
  • 25 kilo pascals
  • 25 kilo-pascals
Prefixes are added without contraction, except as shown here: kilohm
The centi-, deci-, deca-, and hecto- prefixes should generally be avoided; exceptions include centimetre, decibel, hectolitre, hectare, and hectopascal.
  • 100 metres
  • 0.1 km
1 hectometre
Do not use M for 103, MM for 106, or B for 109 (except as noted elsewhere on this page for M and B, e.g. for monetary values) 3 km
8 MW
125 GeV
3 Mm
125 BeV
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 hr 30 min 7 sec
  • 1 h 30 m 7 s
... but are not normally used in SI.
  • 1.33 m
  • 133 cm
1 m 33 cm

Note to table:

  1. ^ 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).
  2. ^ This format is used in astronomy (see the IAU Style Manual[14] for details).

Specific units[edit]

Guidelines on specific units
Group Name Symbol Comment
  • inch
  • foot
  • in
  • ft
Do not use &prime; (), &Prime; (), apostrophe (') or quote (").
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.
knot kn (not "kt or "kN)
  • metre
  • meter (U.S.)
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., au, ua) AU is the most commonly used symbol for this unit, both in popular and professional articles, and is hence also used on Wikipedia (though some organizations, including the "BIPM[13] and "IAU,[15] recommend au).
  • mile
  • miles per hour
  • nautical mile
  • mi
  • mph
  • nmi or NM (not "nm)
In nautical and aeronautical contexts use statute mile rather than mile to avoid confusion with nautical mile.
  • cubic centimetre
  • cubic centimeter (U.S.)
cm3 Markup: cm<sup>3</sup>
cc Non-SI symbol 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 fluid pint
  • US fluid quart
  • US gallon
  • imp fl oz
  • imp pt
  • imp qt
  • imp gal
  • US fl oz
  • US fl pt
  • US fl qt
  • US gal
US or imperial (or imp) must be specified; fluid or fl must be specified for fluid ounces and US units, except with gallon. (Without fluid, "ounce is ambiguous – versus avoirdupois ounce or troy ounce – and US "pint or US "quart are ambiguous – versus US dry pint or US dry quart.)
cubic foot cu ft (not cf) Write five million cubic feet, 5,000,000 cu ft or 5×106 cu ft, not 5 MCF.
cubic foot per second cu ft/s (not cfs)
  • litre
  • liter (U.S.)
l or L The symbol l ("el") in isolation (i.e. not in such forms as ml) is easily mistaken for the digit 1 or the capital letter I ("eye").
  • long ton
  • short ton
Spell out in full.
pound per square inch psi
t (not mt or MT)
troy ounce oz t t or troy must be specified. Articles about precious metals, black powder, and gemstones should always specify whether ounces and pounds are "avoirdupois or "troy.
troy pound lb t
"carat carat Used to express masses of gemstones and pearls.
Purity "carat or karat k or Kt A measure of purity for gold alloys. (Do not confuse with the unit of mass with the same spelling.)
  • second
  • minute
  • hour
  • s
  • min
  • hr
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 or Bps)
"arcminute Markup: &prime;  ("prime ′ not apostrophe/​single quote '). No space (47′, not 47 ).
"arcsecond Markup: &Prime;  ("double prime ″ not double-quote "). No space (22″, not 22 ).
degree ° Markup: &deg; (degree ° not "masculine ordinal º or "ring ̊). No space (23°, not 23 °).
Temp­erature degree ° Markup: &deg;. Use a non-breaking space: 12{{"nbsp}}&deg;C, not 12&deg;C nor 12&deg;{{"nbsp}}C (12 °C, not 12°C nor 12° C).
degree Celsius (not degree centigrade) °C (not C)
"kelvin (not degree kelvin) K (not °K)
  • "calorie
  • small calorie
  • gram calorie
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 therefore also a kilogram calorie.
  • "kilocalorie
  • large calorie
  • kilogram calorie
  • (not Calorie – can be ambiguous)

Quantities of bytes and bits [edit]


In quantities of "bits and "bytes, 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 "SI prefixes), meaning 103, 106, 109, 1012, etc., or they 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 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 multiples of
"bits (bit) or "bytes (B)
Value "SI
1000 k "kilo
10002 M "mega
10003 G "giga
10004 T "tera
10005 P "peta
10006 E "exa
10007 Z "zetta
10008 Y "yotta
1024 Ki "kibi K kilo
10242 Mi "mebi M mega
10243 Gi "gibi G giga
10244 Ti "tebi
10245 Pi "pebi
10246 Ei "exbi
10247 Zi "zebi
10248 Yi "yobi

Follow these recommendations when using these prefixes in Wikipedia articles:

  •  A 64 MB (64 × 10242-byte) video card and a 100 GB (100 × 10003-byte) hard drive
  •  A 64 MB (64 × 220-byte) video card and a 100 GB (100 × 109-byte) hard drive
  •  A 64 MB (67,108,864-byte) video card and a 100 GB (100,000,000,000-byte) hard drive

The "IEC prefixes kibi- (symbol Ki), mebi- (Mi), gibi- (Gi), etc., are generally not to be used except:[16]

Currencies and monetary values[edit]

Choice of currency
Currency names
Currency symbols
  • 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$, A$) 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 (€26, £22 or $34), unless this would be unclear.

  • Exceptions may occur in tables and infoboxes where space is limited e.g. Currencies accepted for deposit: "US$, "SFr, "GB£, ". It may be appropriate to wikilink such uses, or add an explanatory note.

Common mathematical symbols[edit]

Common mathematical symbols
Symbol name Example Markup Comments
"Plus /
x + y {{var|x}} + {{var|y}}
+y +{{var|y}}
"Minus /
xy {{var|x}} &minus; {{var|y}} Do not use hyphen (-) or dashes ({{"ndash}} or {{"mdash}}).
y &minus;{{var|y}}
"Plus-minus /
41.5 ± 0.3 41.5 &plusmn; 0.3
−(±a) = ∓a &minus;(&plusmn;{{var|a}}) = &#8723;{{var|a}}
x × y {{var|x}} &times; {{var|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.
"Division, obelus x ÷ y {{var|x}} &divide; {{var|y}}
"Equal / equals x = y {{var|x}} = {{var|y}}
"Not equal xy {{var|x}} &ne; {{var|y}}
"Approx. equal π ≈ 3.14 {{pi}} &asymp; 3.14
"Less than x < y {{var|x}} &lt; {{var|y}}
"Less or equal xy {{var|x}} &le; {{var|y}}
"Greater than x > y {{var|x}} &gt; {{var|y}}
"Greater or equal xy {{var|x}} &ge; {{var|y}}

Geographical coordinates[edit]

For draft guidance on, and examples of, coordinates for linear features, see "Wikipedia: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:

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 and before any other text or images.

To add 44°06′43″N 87°54′47″W / 44.112°N 87.913°W / 44.112; -87.913 to the top of an article, use either
(which does not require minutes or seconds but does require the user to specify north/ south and east/west) or
(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 (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, or
    |display=inline,title to display in both places.
  • "name
    name=X to label the place on maps (default is PAGENAME)

Thus: {{Coord|44.117|-87.913|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 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 example:

For the city of "Oslo, located at 59° 55′ N, 10° 44′ E:

{{coord|59|55|N|10|44|E}} – which becomes 59°55′N 10°44′E / 59.917°N 10.733°E / 59.917; 10.733

For a country, like "Botswana, less precision is appropriate:

{{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 should be used as needed to ensure that both values have the same level of precision.

"London 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 100 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 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.

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[edit]

Notes and references[edit]

  1. ^ "Wikipedia:Requests for arbitration/Jguk § Principles, "Wikipedia:Requests for arbitration/jguk 2 § Principles, and "Wikipedia:Requests for arbitration/Sortan § Principles
  2. ^ CCTF/09-32: Coordinated Universal Time (UTC) (PDF). "BIPM. 2009-06-02. p. 3. Retrieved 2015-08-20. This coordination began on January 1, 1960, and the resulting time scale began to be called informally 'Coordinated Universal Time.'  
  3. ^ Only certain citation styles use abbreviated date formats. By default, Wikipedia does not abbreviate dates. Use a consistent citation style within any one article. See "WP:Citing sources § Citation style.
  4. ^ See "WP:Manual of Style § Commas.
  5. ^ All-numeric yyyy-mm-dd dates might be assumed to follow the "ISO 8601 standard, which mandates the Gregorian calendar. Also, technically all must be four-digit years, but Wikipedia is unlikely to ever need to format a far-future date beyond the year 9999.
  6. ^ 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 "Wikipedia:Manual of Style/Dates and numbers/Three proposals for change to MOSNUM and "Wikipedia:Manual of Style/Dates and numbers/Date Linking RFC
  7. ^ "Wikipedia talk:Manual of Style/Archive 151 § RFC: Month abbreviations
  8. ^ These formats cannot, in general, be distinguished on sight, because there are usages in which 03-04-2007 represents March 4, and other usages in which it represents April 3. In contrast there is no common usage in which 2007-04-03 represents anything other than April 3.
  9. ^ The number in parentheses is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result – see NIST – Use of concise notation
  10. ^ The 0x and 0 prefixes, but not 0b, are borrowed from the "C programming language.
  11. ^ If there is disagreement about the primary units used in a UK-related article, discuss the matter on the article talk-page, at "MOSNUM talk, 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. Also note the "style guides of British publications such as The Times (see archived version, under "Metric").
  12. ^ These definitions are consistent with all units of measure mentioned in the SI Brochure (see previous footnote) and with all units of measure catalogued in "EU directive 80/181/EEC [1].
  13. ^ a b c "Chapter 4: Non-SI units accepted for use with the SI, and units based on fundamental constants (contd.)". SI Brochure: The International System of Units (SI) (8th ed.). "BIPM. 2014 [2006]. Retrieved 2015-08-20.  Tables 6, 7, 8, and 9 give additional guidance on non-SI units.
  14. ^ Wilkins, G. A. (1989). "5.14 Time and angle". IAU Style Manual (PDF). p. S23. 
  15. ^ "Resolution B2 on the re-definition of the astronomical unit of length" (PDF). International Astronomical Union. 2012. p. 1. 
  16. ^ Wikipedia follows common practice regarding "bytes and other data traditionally quantified using "binary prefixes (e.g. mega- and kilo-, meaning 220 and 210 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-) to distinguish the meaning of the decimal "SI prefixes (e.g. mega- and kilo-, meaning 106 and 103 respectively) from the binary ones, and the subsequent incorporation of these IEC prefixes into the "ISO/IEC 80000, consensus on Wikipedia 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 "WT:Manual of Style (dates and numbers)/Archive/Complete rewrite of Units of Measurements (June 2008).
) )