# Wikipedia:Manual of Style/Dates and numbers

Wikipedia:Manual of Style/Dates and numbers
Shortcuts:
WP:MOSNUM
WP:DATE
MOS:NUM

This part of the Manual of Style helps editors to achieve consistency in the use and formatting of numbers, dates, times, measurements, currencies, and coordinates in Wikipedia articles. Consistency in style and formatting promotes clarity and cohesion; this is especially important within an article. The goal is to make the whole encyclopedia easier and more intuitive to use. Try to write so the text cannot be misunderstood, and take account of what is likely to be familiar to readers—the less they have to look up definitions, the easier it is to be understood.

Where this manual provides options, consistency should be maintained within an article unless there is a good reason to do otherwise. In direct quotations, the original text should be preserved. 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.

## Chronological items

### Precise language

Shortcut:
WP:DATED

Avoid statements that date quickly, except on pages that are regularly updated, like current events pages. Avoid words such as now and soon (unless their intended meaning is clear), currently and recently (except on rare occasions where they are not redundant), or phrases such as in modern times and the sixties. Instead, when writing about past events use more precise phrases such as during the 1990s or in August 1969. For future and current events, use phrases such as as of November 2011 or since the beginning of 2010 that indicate the time-dependence of the information to the reader.

To help editors keep information up to date, statements about current and future events may be used with the as of technique. This is done by using the {{as of}} template to tag information that may become dated quickly: {{as of|2011}} produces the text As of 2011 and categorises the article appropriately. This technique is not an alternative to using precise language. For instance, one should not replace since the start of 2005 with {{as of|2005}} because some information (the start of 2005) would be lost; instead, use either the plain text or a more advanced feature of {{as of}} such as {{as of|2005|alt=since the start of 2005}}.

### Time of day

Shortcuts:
WP:MOSTIME
MOS:TIME

Context determines whether the 12- or 24-hour clock is used; in both, colons separate hours, minutes and seconds (e.g. 1:38:09 pm or 13:38:09).

• 12-hour clock times end with dotted or undotted lower-case a.m. or p.m., or am or pm, preceded by a space (e.g. 2:30 p.m. or 2:30 pm, not 2:30p.m. or 2:30pm). Hours denoted by a single digit should not have a leading zero (e.g. 2:30 p.m., not 02:30 p.m.). A hard space (see above) is advisable (2:30&nbsp;pm or {{nowrap|2:30 p.m.}}). Use noon and midnight rather than 12 pm and 12 am; whether midnight refers to the start or the end of a date will need to be specified unless it is clear from the context.
• 24-hour clock times have no a.m., p.m., noon or midnight suffix. Hours under 10 should have a leading zero (e.g. 08:15). 00:00 refers to midnight at the start of a date, 12:00 to noon, and 24:00 to midnight at the end of a date, but should not be used for the first hour of the next day (e.g. use 00:10 for ten minutes after midnight, not 24:10).

Time of day is normally expressed in figures rather than being spelled out. For details, and information on time intervals (e.g. 5 minutes), see Numbers as figures or words, below.

### Day, month and season names

See Wikipedia:Manual of Style (capital letters)#Calendar items

### Dates

• Wikipedia does not use ordinal suffixes, articles, or leading zeros. Wikipedia does not insert a comma between month and year, nor does it insert a full stop after the day (10 June 1921); however, a comma is required between day and year (mdy format). When a date in mdy format appears in the middle of text, include a comma after the year (The weather on September 11, 2001, was clear and warm). Write out the full year string instead of using the apostrophe (') to abbreviate the first two digits of the year.
Shortcut:
WP:DATESNO
Incorrect Correct
9th June
the 9th of June
9. June
9 June
June 9th June 9
June, 2001 June 2001
9 June, 2001
09 June 2001
9 June 2001
June 9 2001
June 09, 2001
June 9, 2001
• If a date range is abbreviated, use the formats 5–7 January 1979 or January 5–7, 1979 with an unspaced en dash. An unspaced en dash is also used for month or year ranges, such as June–August 1940 or the 1939–45 war. However, between two months and days, use a spaced en dash, such as June 3 – August 18 or June 3, 1888 – August 18, 1940. The space before an en dash should preferably be a non-breaking space (&nbsp;).
• A night may be expressed in terms of the two contiguous dates using a slash (the bombing raids of the night of 30/31 May 1942).
• Do not use year-final numerical date formats (DD-MM-YYYY or MM-DD-YYYY), as they are ambiguous: "03/04/2005" could refer to 3 April or to March 4. For consistency, do not use such formats even if the day number is greater than 12.
• Yearless dates (5 March, March 5) are inappropriate unless the year is obvious from the context. There is no such ambiguity with recurring dates, such as January 1 is New Year's Day.
• Year-initial numerical (YYYY-MM-DD) dates (e.g. 1976-05-31) are uncommon in English prose, and should not be used within sentences. However, they may be useful in long lists and tables for conciseness. (For sorting in tables consider using {{sort|2008-11-01|1 November 2008}} or {{dts|November 1, 2008}}.) Because year-initial dates might be assumed to follow the ISO 8601 standard, which mandates the Gregorian calendar, this format should only be used for dates expressed in the Gregorian calendar and for the years 1583 through 9999.

#### Full date formatting

In general, the following formats are acceptable:

• Month before day: February 14 and February 14, 1990 (comma required)
• Day before month: 14 February and 14 February 1990 (no comma)

Date formatting in an article is governed by the following three guidelines.

##### Format consistency
Shortcut:
MOS:DATEUNIFY
• Dates in article body text should all have the same format:
Correct
Julia ate a poisoned apple on 25 June 2005. She died three days later on 28 June.
Incorrect
Julia ate a poisoned apple on 25 June 2005. She died three days later on June 28.
##### In references
• Publication dates in article references should all have the same format.
In the same article, write
• Jones, J. (20 Sep 2008)
• Smith, J. (Sep 2002)
but not
• Jones, J. (20 Sep 2008)
• Smith, J. (September 2008)
• Access and archive dates in references should be in either the format used for publication dates, or YYYY-MM-DD.
In the same article, write
• Jones, J. (20 Sep 2008) ... Retrieved 5 Feb 2009.
or
• Jones, J. (September 20, 2008) ... Retrieved 2009-02-05.
but not
• Jones, J. (20 Sep 2008) ... Retrieved February 5, 2009.

These requirements do not apply to dates in quotations or titles.

##### Strong national ties to a topic
Shortcut:
WP:STRONGNAT
• Articles on topics with strong ties to a particular English-speaking country should generally use the more common date format for that nation. For the US this is month before day; for most others it is day before month. Articles related to Canada may use either format consistently.
• Sometimes the customary format differs from the usual national one: for example, articles on the modern US military use day before month, in accordance with military usage.
##### Retaining the existing format
Shortcut:
WP:DATERET
• If an article has evolved using predominantly one format, the whole article should conform to it, unless there are reasons for changing it based on strong national ties to the topic.
• The date format chosen by the first major contributor in the early stages of an article should continue to be used, unless there is reason to change it based on strong national ties to the topic.
• 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".

#### Dates of birth and death

Shortcuts:
MOS:DOB
WP:MOSBD

At the start of articles on people, their dates of birth and death are provided. For example: "Charles Robert Darwin FRS (12 February 1809 – 19 April 1882) was an English naturalist ..." The two dates are separated by an en dash (HTML code &ndash;). When either date contains a space, the en dash is preceded by a space (preferably a non-breaking space, code &nbsp;) and followed by a space. When full dates are provided in the text or in an infobox, year-pairs can be sufficient for the lede in some cases; in such cases no spaces are used, e.g. "(1943–1971)".

• For an individual still living: "Serena Williams (born September 26, 1981) ...", not "... (September 26, 1981 –) ..."
• When only the years are known: "Socrates (470–399 BC) was..."
• When the year of birth is completely unknown, it should be extrapolated from earliest known period of activity: "Offa of Mercia (before 734 – 26 July 796) ..."
• When the year of birth is probable but not known for certain: "Genghis Khan (1162? – August 1227) ..."
• When the years of both birth and death are known only approximately: "Dionysius Exiguus (c. 470 – c. 540) ..."
• When the date of death is completely unknown, it should be extrapolated from last known period of activity: "Robert Menli Lyon (1789 – after 1863) ..."
• When the reign of a sovereign is uncertain: "Rameses III (reigned c. 1180 BCE – c. 1150 BCE) ..."
• When the individual is known to have been alive (flourishing) at certain dates, [[floruit|fl.]] or {{fl.}} is used in articles, not disambiguation pages, to link to floruit, in case the meaning is not familiar: "Osmund (760–772fl. 760–772) ..."
• When the individual is known to have been alive as early as about 660, and to have died in 685: "Aethelwalh (c. 660 – 685fl. c. 660 – 685) ..."

In biographical infobox templates, provide age calculation and microformat compatibility with date mathematics templates. See the documentation for those templates in order to use them properly, and Wikipedia:Manual of Style (biographies) for more guidelines on articles about people.

#### Other date ranges

Shortcuts:
WP:OTHERDATE
WP:DATEOTHER

Dates that are given as ranges should follow the same patterns as given above for birth and death dates.

#### Linking and autoformatting of dates

Shortcuts:

Dates should not be linked purely for the purpose of autoformatting (even though linking was previously recommended).[2] Dates should only be linked when they are germane and topical to the subject, as discussed at Wikipedia:Linking#Chronological items.

### Longer periods

• Months are expressed as whole words (February, not 2), except in the YYYY-MM-DD format. Unlike some other languages, the names of months and days of the week are capitalised in English. Abbreviations such as Feb. in the United States or Feb in most other countries are used only where space is extremely limited, such as in tables and infoboxes. Do not insert of between a month and a year (April 2000, not April of 2000).
• Seasons. As the seasons are reversed in the northern and southern hemispheres—and areas near the equator tend to have just wet and dry seasons—neutral wording (in early 1990, in the second quarter of 2003, around September) is usually preferable to a "seasonal" reference (summer 1918, spring 1995). Even when the season reference is unambiguous (for instance when a particular location is clearly involved) a date or month may be preferable to a season name, unless there is a logical connection (the autumn harvest). Season names are preferable, however, when they refer to a phase of the natural yearly cycle (migration to higher latitudes typically starts in mid-spring). Seasons are normally spelled with a lower-case initial.
• Years
• Years are normally expressed in digits. Avoid inserting the words the year before the digits (1995, not the year 1995), unless the meaning would otherwise be unclear.
• Year ranges, like all ranges, are normally separated by an en dash, not a hyphen or slash: 2005–06 is a two-year range, whereas 2005/06 is a period of twelve months or less, such as a sports season or a financial year.
• A closing CE or AD year is normally written with two digits (1881–86) unless it is in a different century from that of the opening year, in which case the full closing year is given (1881–1986).
• A closing BCE or BC year is given in full (2590–2550 BCE). While one era signifier at the end of a date range requires an unspaced en dash (12–5 BC), a spaced en dash is required when a signifier is used after the opening and closing years (5 BC – AD 29).
• Ranges expressed using prepositions (from 1881 to 1886 or between 1881 and 1886) should not use en dashes (not from 1881–1886 or between 1881–1886).
• To indicate around, approximately, or about, the unitalicised abbreviation c. is preferred over circa, ca, ca., approximately, or approx., and should be spaced (c. 1291). Do not use a question mark for this function (1291?), as this may imply to the reader an uncertainty on the part of Wikipedia editors rather than on the part of reliable historians.
• Decades as such contain neither an apostrophe nor the suffix -ies (the 1980s, not the 1980's, not the 1980-ies, and definitely not the 1980s'). The two-digit form is never used in reference to the decade as a time span per se.
• The two-digit form, to which a preceding apostrophe should be added, is used only in reference to a social era or cultural phenomenon that roughly corresponds to and is said to define a decade, and only if it is used in a sourceable stock phrase (the Roaring '20s, the Gay '90s), or when there is a notable connection between the period and what is being discussed in the sentence (a sense of social justice informed by '60s counterculture, but grew up in 1960s Boston, moving to Dallas in 1971). Such an abbreviation should not be used if it would be redundant ('80s Reaganomics) or if it does not have a clear cultural significance and usage (the '10s).
• Centuries and millennia
• For purposes of written style, the English Wikipedia does not recognise a year 0. Therefore, for dates AD (or CE) the 1st century was 1–100, the 17th century was 1601–1700, and the second millennium was 1001–2000; for dates BC (or BCE) the 1st century was 100–1; the 17th century was 1700–1601, and the second millennium was 2000–1001.
• Forms such as the 1700s are normally best avoided since it may be unclear whether a 10 or 100 year period is meant (i.e. 1700–1709 or 1700–1799). It should also be noted that the 18th century (1701–1800) and the 1700s (1700–1799) do not span the same period.

### Year numbering systems

• Years are numbered according to the traditional western Dionysian era (Common Era).
• AD and BC are the traditional ways of referring to these eras. CE and BCE are common in some academic and religious writing. No preference is given to either style.
• Do not use CE or AD unless the date or century would be ambiguous without it (e.g. "The Norman Conquest took place in 1066" not 1066 CE or AD 1066). On the other hand, "Plotinus was a philosopher living at the end of the 3rd century AD" will avoid unnecessary confusion. Also, in "He did not become king until 55 CE" the era marker makes it clear that "55" does not refer to his age. Alternatively, "He did not become king until the year 55."
• BCE and CE or BC and AD are written in upper case, unspaced, without periods (full stops), and separated from the year number by a space or non-breaking space (5 BC, not 5BC).
• Use either the BC-AD or the BCE-CE notation, but be consistent within the same article. AD may appear before or after a year (AD 106, 106 AD); the other abbreviations appear after (106 CE, 3700 BCE, 3700 BC).
• Do not arbitrarily change from one style to the other on any given article. Instead, attempt to establish a consensus for change at the talk page.
• Uncalibrated (bce) radiocarbon dates: Some source materials will indicate whether a date is calibrated or not simply by a change in capitalisation; this is often a source of confusion for the unwary reader. Do not give uncalibrated radiocarbon dates (represented by the lower-case bce unit, occasionally bc or b.c. in some sources), except in directly quoted material, and even then include a footnote, a square-bracketed editor's note [like this], or other indication to the reader what the calibrated date is, or at least that the date is uncalibrated. Calibrated and uncalibrated dates can diverge surprisingly widely, and the average reader does not recognise the distinction between bce and BCE / BC.
• Abbreviations indicating long periods of time ago—such as BP (before present), as well as various annum-based units such as ka (kiloannum), Ma (megaannum) and Ga (gigaannum) are given as full words on first occurrence. Where source quotations use the abbreviations tya or kya (thousand years ago), mya (million years ago), or bya (billion years ago) this should be explained to the reader, as in "a measured Libby radiocarbon date of 35.1 mya [million years ago] had to be calibrated ..." The tya/kya, mya and bya symbols are deprecated in some fields such as geophysics and geology, but remain common in others, such as anthropology.
• BP: Do not convert other notations to BP unless you are certain of what you are doing. The difference between calibrated and uncalibrated BP dates can be significant. In most scientific and academic contexts the unit BP is actually defined as "years before January 1, 1950", not "years before the literal present", and the conversion may introduce an error if the date being converted is not a wide approximation (18,000 BP) but a more narrow one or an actual known year. BP years are given as 18,000 BP or spelled out as 18,000 years before present (not 18,000 YBP, 18,000 before present, 18,000 years before the present, or similar.) A safer and less complex alternative may be to just use "years ago", which is used by many leading authorities, such as the British Museum.

### Calendars

Dates can be given in any appropriate calendar, as long as the date in either the Julian or Gregorian calendars is provided, 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, this must be clear to readers.

• Current events are given in the Gregorian calendar.
• Dates before the adoption of the Gregorian calendar on 15 October 1582 are normally given in the Julian calendar. The Julian day and month should not be converted to the Gregorian calendar, but the start of the Julian year should be assumed to be 1 January (see below for more details).
• Dates for Roman history before 45 BC are given in the Roman calendar, which was neither Julian nor Gregorian. When (rarely) the Julian equivalent is certain, it may be included.
• The Julian or Gregorian equivalent of dates in early Egyptian and Mesopotamian history is often debatable. Follow the consensus of reliable sources, or indicate their divergence.
• Dates of events in countries using the Gregorian calendar are given in the Gregorian calendar. This includes some of the Continent of Europe from 1582, the British Empire from 14 September 1752, and Russia from 14 February 1918 (see the Gregorian calendar article).

The dating method used should follow that used by reliable secondary sources. If the reliable secondary sources disagree, choose the most common used by reliable secondary sources and note the usage in a footnote.

At some places and times, dates other than 1 January were used as the start of the year. The most common English-language convention was the Annunciation Style used in Britain and its colonies, in which the year started on 25 March, Annunciation Day; see the New Year article for a list of other styles. 1 January is assumed to be the opening date for years; if there is reason to use another start-date, this should be noted.

If there is a need to mention Old Style 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).

### Time zones

Shortcut:
WP:TIMEZONE

When writing a date, first consider where the event happened and use the time zone there. For example, the date of the attack on Pearl Harbor should be December 7, 1941 (Hawaii time/date). If it is difficult to judge where, consider what is significant. For example, if a vandal based in Japan attacked a Pentagon computer in the US, use the time zone for the Pentagon, where the attack had its effect. If known, include the UTC date and time of the event in the article, indicating that it is UTC.

## Numbers

### Numbers as figures or words

As a general rule, in the body of an article, single-digit whole numbers from zero to nine are spelled out in words; numbers greater than nine are commonly rendered in numerals, or in words if they are expressed in one or two words (16 or sixteen, 84 or eighty-four, 200 or two hundred, but 3.75, 544, 21 million). This applies to ordinal numbers as well as cardinal numbers. However there are frequent exceptions to these rules.

• In tables and infoboxes, quantitative data is expressed as numerals; numerals will also fit better in limited space. Numbers within a table's explanatory text and comments should be consistent with the general rule.
• Comparable quantities should be all spelled out or all figures: we may write either 5 cats and 32 dogs or five cats and thirty-two dogs, not five cats and 32 dogs.
• Adjacent quantities which are not comparable should usually be in different formats: twelve 90-minute volumes or 12 ninety-minute volumes is more readable than 12 90-minute volumes or twelve ninety-minute volumes.
• Numbers that begin a sentence are spelled out, since using figures risks the period being read as a decimal point or abbreviation mark; it is often better to recast the sentence than to simply change format, which may produce other problems; e.g. do not use Nineteen forty five and 1950 were important elections for the Labour Party, but rather The elections of 1945 and 1950 were important for the Labour Party.
• The numerical elements of dates and times are not normally spelled out (that is, do not use the seventh of January or twelve forty-five p.m. or Two thousand eight was the year that ... ). However, they should be spelled out where customary in historical references such as Seventh of March Speech and Fifth of November; these are treated as proper names.
• Centuries are given in figures or words using adjectival hyphenation where appropriate: the 5th century BCE; nineteenth-century painting. Neither the ordinal nor the word "century" should be capitalised.
• Simple fractions are normally spelled out; use the fraction form if they occur in a percentage or with an abbreviated unit (14 yd or a quarter of a yard, but not a quarter of a yd) or if they are mixed with whole numerals.
• Decimal representations containing a decimal point are not spelled out (1.00, 3.14159).
• Numbers in mathematical formulae are never spelled out (3 < π < 22/7, not three < π < 22 sevenths).
• Do not use spelled-out numbers before symbols for units of measurement: write five minutes, 5 minutes, or 5 min, but not five min.
• Measurements, stock prices, and other quasi-continuous quantities are normally stated in figures, even when the value is a small positive integer: 9 mm, The option price fell to 5 within three hours after the announcement.

### Fractions

• The template {{frac}} is available for representing common fractions. For pq, type {{frac|p|q}}. For N pq, type {{frac|N|p|q}}. When copied and pasted, N pq will appear as N+p/q.
• Unless there is sound reason to the contrary, fractional parts of metric units should be expressed as decimal fractions (5.25 mm), not vulgar fractions (5 1/4 mm). However Imperial, English, avoirdupois, and United States customary units may use either form – both (5.25 inches) and (5 1/4 inches) are acceptable, provided that there is consistency in the way that the fractions are represented.
• In science and mathematics articles, fractions should always be written either with a horizontal fraction bar (as in $\textstyle\frac{1}{2}$), or with a forward slash and with the baseline of the numbers aligned with the baseline of the surrounding text (as in 1/2). The use of {{frac}} (such as 12) is discouraged in these articles.
• The use of the few Unicode symbols available for fractions (such as ½) is discouraged entirely, for accessibility reasons among others.
• Use of the ordinal suffix (e.g., th) in fractions expressed in numerals is discouraged (e.g. 1/100, not 1/100th).

### Decimal points

• A decimal point is used between the integer and the fractional parts of a decimal; a comma is never used in this role (6.57, not 6,57).
• The number of decimal places should be consistent within a list or context (The response rates were 41.0 and 47.4 percent, respectively, not The response rates were 41 and 47.4 percent, respectively), except if the quantities were measured with different precisions.
• Numbers between −1 and +1 require a leading zero (0.02, not .02); exceptions are sporting performance averages (.430 batting average) and commonly used terms such as .22 calibre.

### Percentages

Shortcuts:
MOS:PERCENT
WP:PERCENT
WP:%
• Percent (American English) or per cent (British English) is commonly used to indicate percentages in the body of an article. The symbol % is more common in scientific or technical articles and in complex listings.
• The symbol is unspaced (71%, not 71 %).
• In tables and infoboxes, the symbol % is normally preferred to the spelled-out percent or per cent.
• Ranges should be formatted with one rather than two percentage signifiers (22–28%, not 22%–28%).
• Avoid ambiguity in expressing a change of rates. This can be done by using percentage points, not percentages, to express a change in a percentage or the difference between two percentages; for example, The agent raised the commission by five percentage points, from 10 to 15% (if the 10% commission had instead been raised by 5%, the new rate would have been 10.5%). It is often possible to recast the sentence to avoid the ambiguity (raised the commission from 10% to 15%). Percentage point should not be confused with basis point, which is a hundredth of a percentage point.

### Repeating decimals

The preferred way to indicate a repeating decimal is to place a bar over the digits that repeat. To achieve this the template {{overline}} can be used. For example, the markup 14.{{overline|285714}} gives 14.285714.

Consider a short explanation of this notation (called a vinculum) the first time it is used in an article. Some authors place the repeating digits in parentheses rather than using an overbar (perhaps because overbars are not available in their typesetting environment) but this should be avoided in Wikipedia to avoid confusion with expressing uncertainty.

### Non-base-10 notations

For numbers expressed in bases other than base ten:

• In computer-related articles, use the C programming language prefixes 0x (zero-ex) for hexadecimal and 0 (zero) for octal. For binary, use 0b. Consider including a note at the top of the page about these prefixes.
• In all other articles, use subscript notation. For example: 1379, 2416, 2A912, A87D16 (use <sub> and </sub>).
• For base eleven and higher, use whatever symbols are conventional for that base. One quite common convention, especially for base 16, is to use upper-case A–F for digits from 10 through 15 (0x5AB3).

### Scientific notation, engineering notation, and uncertainty

#### Notations

• The template {{val}} can be used to facilitate the generation of scientific notation. It is a flexible tool that allows editors great latitude and must have arguments (each section between the vertical bars) properly entered in order for it to generate output that is compliant with formatting conventions.
• Scientific notation is done in the format of one leading digit/decimal marker/remaining digits/×10n, where n is the integer that gives one leading digit.
• 1.602×10−19 is a proper use of scientific notation.
• 160.2×10−17 is not a proper use of scientific notation.
• Engineering notation is done in the format of leading digits/decimal marker/remaining digits/×10n, where n is a multiple of 3. The number of leading digits is adjusted accordingly.
• 132.23×106 is a proper use of engineering notation.
• 1.3223×108 is a not proper use of engineering notation.
• It is clearer to avoid mixing scientific notation and engineering notation in the same context (e.g., do not write A 2.23×102 m2 region covered by 234.0×106 grains of sand).
• Use discretion when it comes to using scientific and engineering notation. Not all values need to be written in it.
• Sometimes it is useful to compare values with the same power of 10 (often in tables) and scientific or engineering notation might not be appropriate.

#### Uncertainty

• Uncertainties can be written in various ways:
• Value/±/uncertainty/×/10n/unit symbol (e.g., 1.534±0.35×1023 m)
• Do not group value and uncertainty in parenthesis before the multiplier (e.g., do not write (15.34 ± 0.35) × 1023 m)
• Value/superscript positive uncertainty/subscript negative uncertainty/×/10n/unit symbol (e.g., 15.34+0.43
−0.23
×1023 m
)
• Value(uncertainty in the last digits)/×/10n/unit symbol (e.g., 1.604(48)×10−4 J)
• Value/±/relative uncertainty(percent)/unit symbol (e.g., 12.34 ± 5% m2)
• The template {{val}} may be used to automatically handle all of this.

## Units of measurement

Shortcuts:
WP:UNIT
WP:UNITS
WP:MEASUREMENT

### Which units to use

For many articles, Wikipedia has adopted a system of writing a "main" unit followed by a conversion in parentheses (see Unit conversions below).

• In non-science US-related articles: the main unit is generally a US customary unit (22 pounds (10 kg)).
• In non-science UK-related articles: the main unit is generally a metric unit (10 kg (22 pounds)), but imperial units are still used as the main units in some contexts, including:[3]
• miles for road distances, miles per hour for road speeds, and miles per imperial gallon for fuel consumption;
• feet/inches and stone/pounds for personal height and weight measurements;
• imperial pints for draught beer/cider and bottled milk.
How to present the units
• Avoid mixing systems of measurement used for primary measures. Write They could see the peak of a 600‑metre (2,000 ft) hill from a nearby 650‑metre (2,100 ft) hill, not …a 2,000‑foot (610 m) hill from a nearby 650‑metre (2,100 ft) hill.
• Nominal and defined values should be given in the original units first, even if this makes the article inconsistent: for example, When the Republic of Ireland adopted the metric system, the road speed limit in built-up areas was changed from 30 miles per hour (48 km/h) to 50 kilometres per hour (31 mph). (The focus is on the change of units, not on the 3.6% increase.)
• Measurements should be accompanied by a proper citation of the source using a method described at the style guide for citation.
• In cases where the primary measurement in the article is different from the primary measurement in the source:
• Ensure that the precision of the converted unit in the article appropriately matches the precision of the value from the source.
• Consider quoting the source measurement in the citation, particularly when the source only provides one system of units.
• In some cases it may be useful to avoid this by taking the unit used by the source as primary.

#### SI standard

• SI units are written according to the SI standard unless otherwise specified in this Manual of Style (dates and numbers). For example see American spelling.
• Non-SI units in tables 6, 7, 8, and 9 of the SI brochure are written according to the SI standard unless otherwise specified in this Manual of Style (dates and numbers). For example see guidance on litre.
• Non-SI units mentioned elsewhere in the SI brochure are written according to the SI standard unless otherwise specified in this Manual of Style (dates and numbers). For example see Percentages.

### Unit conversions

Shortcuts:
MOS:CONVERSIONS
WP:MOSCONVERSIONS

Where English-speaking countries use different units for the same measurement, follow the "primary" unit with a conversion in parentheses. This enables more readers to understand the measurement. Examples: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,375 kilometres (1,476 mi) long.

• With imperial units which are not also US customary units, double conversions can be useful: The song's second verse reveals that Rosie weighs 19 stone (266 lb; 121 kg).
• 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).
• When units are part of the subject of a topic—nautical miles in articles about the history of nautical law, SI units in scientific articles, yards in articles about American football—it can be excessive to provide conversions every time a unit occurs. It could be best to note that this topic will use the units (possibly giving the conversion factor to another familiar unit in a parenthetical note or a footnote), and link the first occurrence of each unit but not give a conversion every time it occurs.
• Converted values should use a level of precision similar to that of the source value, so the Moon is 380,000 kilometres (240,000 mi) from Earth, not (236,121 mi). However, small numbers may need to be converted to a greater level of precision where rounding would cause a significant distortion, so one mile (1.6 km), not one mile (2 km).
• Category:Conversion templates can be used to convert and format many common units, including {{convert}}, which includes non-breaking spaces.
• In a direct quotation, always keep the source units.
• Conversions required for units cited within direct quotations should appear within square brackets in the quote.
• Alternatively, you can annotate an obscure use of units (e.g. five million board feet of lumber) with a footnote that provides conversion in standard modern units, rather than changing the text of the quotation. See the style guide for citation, footnoting and citing sources.
• In tables and infoboxes, use unit symbols and abbreviations—do not spell them out.

### Unit names and symbols

Unit names and symbols should follow the practice of reliable sources; the following guidelines may be helpful:

#### Conventions

• Where space is limited, such as in tables, infoboxes, and parenthetical notes, and in mathematical formulas, unit symbols are preferable. In prose it is usually better to spell out unit names, but symbols may also be used when a unit (especially one with a very long name) is used many times in an article. However, spell out the first instance of each unit in an article (for example, the typical batch is 250 kilograms ... and then 15 kg of emulsifier is added), except for unit names which are hardly ever spelled out even in publications for general audiences (e.g. the degree Celsius).
• If a unit symbol which can be unfamiliar to a general audience is used in an article, it should be shown parenthetically after the first use of the full unit name: for example, His initial betatron reached energies of 2.3 megaelectronvolts (MeV), while subsequent betatrons achieved 300 MeV.
• Numerical ranges use unspaced en dashes if only one unit symbol is used at the end (e.g. 5.9–6.3 kg), and spaced en dashes if two symbols are used (e.g., 3 μm – 1 mm); ranges in prose can be specified using either unit symbol or unit names, and units can be stated either after both numerical values or after the last (e.g., from 5.9 to 6.3 kilograms, from 5.9 kilograms to 6.3 kilograms, from 5.9 to 6.3 kg and from 5.9 kg to 6.3 kg are all acceptable).
• When dimensions are given, each number should be followed by a unit name or symbol (e.g., write 1 m × 3 m × 6 m, not 1 × 3 × 6 m or 1 × 3 × 6 m3).
##### Unit names
• Unit names are common nouns. Write them in lower case except where: common nouns take a capital; otherwise specified in the SI brochure; otherwise specified in this manual of style.
• When unit names are combined by multiplication, separate them with a hyphen or space (e.g., newton-metre or newton metre). The plural is formed by pluralising the last unit name (e.g., ten newton-metres).
• When unit names are combined by division, separate them with per (e.g., meter per second, not meter/second). The plural is formed by pluralising the unit preceding the per, since it reads this many units of this per one unit of this (e.g., ten metres per second).
• When they form a compound adjective, values and unit names should be separated by a hyphen: for example, a five-day holiday.
##### American spelling

American spellings of unit names should be used on pages written in American English. See "Specific units" section.

##### Unit symbols
• Units symbols are preceded by figures, not by spelled-out numbers: for example, 5 min, not five min.
• Values and unit symbols are separated by a non-breaking space. The {{nowrap}} template or the &nbsp; character can be used for this purpose. For example, use 10 m or 29 kg, not 10m or 29kg.
• Exceptions: Non-alphabetic symbols for degrees, minutes and seconds for angles and coordinates and the percent sign are unspaced (for example, 5° 24′ 21.12″ N for coordinates, 90° for an angle, 47% for a percentage, but 18 °C for a temperature). See also Manual of Style—Geographical Coordinates.
• Write unit symbols in upright roman type. (Italic type is normally reserved for variables and the like.) (e.g., 10 m or 29 kg, not 10 m or 29 kg).
• Standard symbols for units are undotted; e.g., m for the metre (not m.), kg for the kilogram (not kg.), in for the inch (not in., the quotation mark ", or the double prime ), and ft for foot (not ft., the apostrophe ', or the prime ).
• Non-standard abbreviations should be dotted.
• Symbols are identical in singular and plural—an s is never appended e.g., km, in, lb, not kms, ins, lbs.
• When unit symbols are combined by multiplication, use a middle dot (&middot;) or a non-breaking space (&nbsp;) to separate the symbols. For example, ms is the symbol for the millisecond, while m·s or m s is the symbol for the metre-second.
• When unit symbols are combined by division, use a slash to separate the symbols (e.g., for the metre per second use the symbol m/s, not mps) or use negative exponents (m·s−1). Exceptions include mph for the mile per hour, psi for pounds per square inch, etc.
• There should be no more than one slash per compound unit symbol (e.g., kg/(m·s), not kg/m/s or kg/m·s).
• Write powers of unit symbols with html e.g. 5 km<sup>2</sup> not Unicode superscripts and subscripts. Html superscripts are easier to read.
• The abbreviations sq and cu (e.g., 15 sq mi and 3 cu ft may be used for US customary and imperial units but not for SI units.
• Unit symbols/abbreviations, apart from those listed below, are written in either non-alphabetic characters or in lower-case letters unless they are derived from a proper name, in which case the first letter is a capital letter.[4] (This applies to the unit itself, not its prefix).
• Roman prefixes are not used (M for 103, MM for 106, B for 109). Use SI prefixes instead.

#### Quantities of bytes and bits

Shortcut:
WP:COMPUNITS

In quantities of bits and bytes, the prefixes kilo (symbol k or K), mega (M), giga (G), etc. are ambiguous. They may be based on a decimal system (like the standard SI prefixes), meaning 103, 106, 109, etc., or they may be based on a binary system, meaning 210, 220, 230, 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 bit and byte multiples
Decimal
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
Binary
Value IEC JEDEC
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:

• Specify if the binary or decimal meanings of K, M, G, etc. are intended as the primary meaning. Consistency within each article is desirable, but the need for consistency may be balanced with other considerations.
• The definition most relevant to the article should be chosen as primary for that article, e.g., specify a binary definition in an article on RAM, decimal definition in an article on hard drives, bit rates, and a binary definition for Windows file sizes, despite files usually being stored on hard drives.
• Where consistency is not possible, specify wherever there is a deviation from the primary definition.
• Disambiguation should be shown in bytes or bits, with clear indication of whether in binary or decimal base. There is no preference in the way to indicate the number of bytes and bits, but the notation style should be consistent within an article. Acceptable examples include:
A 64 MB (64 × 10242 bytes) video card and a 100 GB (100 × 10003 bytes) hard drive
A 64 MB (64 × 220 bytes) video card and a 100 GB (100×109 bytes) hard drive
A 64 MB (67,108,864 bytes) video card and a 100 GB (100,000,000,000 bytes) hard drive
• Avoid inconsistent combinations such as A 64 MB (67,108,864 bytes) video card and a 100 GB (100 × 10003 bytes) hard drive. Footnotes, such as those seen in Power Macintosh 5500, may be used for disambiguation.
• Unless explicitly stated otherwise, one byte is eight bits (see History of byte).
• A capital K can be used for "kilo-" when it means 1024 in computing contexts.

The IEC prefixes kibi-, mebi-, gibi-, etc. (symbols Ki, Mi, Gi, etc.) are not familiar to most Wikipedia readers (see Complete rewrite of Units of Measurements (June 2008)), so are generally not to be used except under the following circumstances:

• when the article is on a topic where the majority of cited sources use the IEC prefixes,
• when directly quoting a source that uses the IEC prefixes,
• in articles specifically about or explicitly discussing the IEC prefixes.

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). Despite the IEC's 1998 guideline 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, consensus on Wikipedia currently favours the retention of the binary prefixes in computing-related contexts. Use 256 MB of RAM, not 256 MiB of RAM.

### Specific units

Name Symbol Comment
arcminute Equal to 1/60 degree (angle). Avoid apostrophe (') as symbol for this purpose.
arcsecond Equal to 1/60 arcminute. Avoid double quote (") as symbol for this purpose.
bit bit Other symbols for bit (such as b or B) should be replaced with bit. This is to reduce confusion with byte. Similarly, bps should be replaced with bit/s.
byte B or byte Other symbols for byte (such as b or o (French: octet)) should be replaced with B or byte. This is to reduce confusion with bit. Similarly, kBps or KBps should be replaced with kB/s or kbyte/s.
gram calorie cal Also known as the small calorie. Lower case 'c' in symbol. SI prefixes can be used e.g. "kilocalorie". Ambiguous unit: in science or technology (e.g. chemistry or nuclear energy) calorie refers to the gram calorie; in food calorie may refer to the kilogram calorie. SI units should always be provided to eliminate ambiguity.
kilogram calorie Cal Also known as the large calorie. Upper case 'C' in symbol. Ambiguous unit: in science or technology (e.g. chemistry or nuclear energy) calorie refers to the gram calorie; in food calorie may refer to the kilogram calorie. SI units should always be provided to eliminate ambiguity. Do not use metric prefixes with the large calorie. The regular rules for common nouns apply to the calorie. Write 100 calories not 100 Calories.
cubic centimetre cm3 The non-SI symbol cc may be used to refer to engine volume e.g. Honda motorcycles engines. The form cc must be linked to cubic centimetre on first use in each article.
degree ° (&deg;); Other symbols (e.g., masculine ordinal º or ring should be replaced. The degree is used for temperature and angle.
degree centigrade °C A synonym for degree Celsius. May be used in quotations and historical contexts, otherwise should be replaced by degree Celsius.
foot ft Similarly 'foot per second' is ft/s rather than fps. Cubic foot is cu ft rather than cf, 'cubic foot per second' is cu ft/s rather than cfs. One million cubic feet is 1 million cubic feet or 1,000,000 cu ft rather than 1 MCF
imperial fluid ounce imp fl oz The version (imperial) must be specified. The version (fluid) must be specified to avoid confusion with ounce weight. Same applies to pint and quart.
imperial gallon imp gal The version (imperial) must be specified.
knot kn The symbol 'kt' is reserved for kilotonne. The symbol 'kN' is reserved for kilonewton.
litre

(liter in American English)

l or L The symbol l can look like the digit 1 when without prefix.
long ton long ton This unit must always be spelled out in full.
metre

(meter in American English)

m
micron μm A synonym for micrometre. A link to micrometre is required on first use in each article. The symbol μ may be used in quotations and historical contexts, otherwise it should be replaced by μm.
mile mi Use statute mile rather than mile in nautical and aeronautical contexts to avoid confusion with nautical mile.
mile per hour mph
nautical mile nmi (or NM) The symbol nm is reserved for nanometre. Use nautical mile rather than mile in nautical and aeronautical contexts to avoid confusion with statute mile.
pound per square inch psi
short ton short ton This unit must always be spelled out in full.
tonne

(metric ton in American English)

t Other symbols (such as mt or MT) should be replaced with t.
troy ounce ozt The version (troy) must be specified. Same applies to troy pound. Ambiguity with this unit is so frequent that articles about precious metals, black powder, and gemstones should always specify whether ounces and pounds are avoirdupois or troy.
US fluid ounce US fl oz The version (US) must be specified. The version (fluid) must be specified to avoid confusion with ounce weight. Same applies to pint and quart.
US gallon US gal The version (US) must be specified.
year a SI prefixes can be used e.g. "540 Ma old"

## Currencies

Shortcuts:

#### Formatting

• Use the full abbreviation of a currency on its first appearance (e.g. A$52); subsequent occurrences can use just the symbol of the currency (e.g.$88), unless this would be unclear. The exception to this is in articles related entirely to EU-, UK- or US-related topics, in which the first occurrence may also be shortened (€26, £22 or $34 respectively), unless this would be unclear. When there are different currencies using the same symbol in an article, use the full abbreviation (e.g. US$ for the US dollar and A$for the Australian dollar, rather than just$), unless the currency which is meant is clear from the context.
• Do not place a currency symbol after the value (e.g. 123$, 123£, 123€), unless the symbol is normally written as such. Do not write$US123 or $123 (US). • Currency abbreviations that come before the number are unspaced if they consist of or end in a symbol (£123, €123), and spaced if alphabetic (R 75). • If there is no common English abbreviation or symbol, use the ISO 4217 standard. • Format ranges with one, rather than two, currency signifiers ($250–300, not $250–$300).
• Conversions of less familiar currencies may be provided in terms of more familiar currencies, such as the US dollar, euro or pound sterling. Conversions should be in parentheses after the original currency, rounding to avoid excess or false precision (one or two significant digits are usually enough, as the exchange rates can vary significantly) and noting the conversion as approximate, with at least the year given as a rough point of conversion rate reference; e.g., Since 2001 the grant has been 10,000,000 Swedish kronor (approx. US$1.4M, €1.0M, or £800k as of August 2009), not (US$1,390,570, €971,673 or £848,646).
• For obsolete currencies, provide if possible an equivalent, formatted as a conversion, in the modern replacement currency (e.g., decimal pounds for historical pre-decimal pounds-and-shillings figures), or at least a US-dollar equivalent as a default in cases where there is no modern equivalent.
• When possible, always link the first occurrence of lesser-known currencies ().
• The names of currencies, currency subdivisions, coins and banknotes should not be capitalised except where normal capitalisation rules require this (for example, at the start of a sentence).
• When called on to use a plural with the euro, use the standard English plurals and not the "legislative" plurals (ten euros and fifty cents, not ten euro and fifty cent). In adjectival use, no plural form is generally used, but rather a hyphenated form: (a two-euro pen, a ten-dollar meal, a ten-cent coin).
• The pound sterling is represented by the £ symbol, with one horizontal bar. The double-barred symbol is ambiguous, as it has also been used for the Italian lira and other currencies. For non-British currencies that use pounds or a pound symbol (e.g. the Irish pound, IR£) use the symbol conventionally preferred for that currency.

## Common mathematical symbols

• For a negative sign or subtraction operator, use a minus sign (). You can input a minus sign by either keying in &minus; or by clicking on it in the insert box beneath the edit window (located between the ± and × signs). Do not use an en dash (), do not use a hyphen (-) unless writing code, and do not use an em dash ().
• For a multiplication sign, use ×, which can be input by clicking on it in the edit toolbox under the edit window or by keying in &times; (however, the letter x is accepted as a substitute for by in such terms as 4x4).
Common mathematical symbols
Name Operation Other use Symbol CER NCR Unicode As binary operator
(e.g., 1 + 1)
As unary operator
(e.g., +1)
Plus sign Addition Positive sign + &plus; &#43; U+002B Spaced Unspaced
Minus sign Subtraction Negative sign &minus; &#8722; U+2212 Spaced Unspaced
Plus or minus Addition or subtraction Positive or negative sign ± &plusmn; &#177; U+00B1 Spaced Unspaced
Minus or plus Subtraction or addition Negative or positive sign &#8723; U+2213 Spaced Unspaced
Multiplication sign, cross Multiplication, vector product × &times; &#215; U+00D7 Spaced
Division sign, obelus Division ÷ &divide; &#247; U+00F7 Spaced
Equal sign Equation = &#61; U+003D Spaced
Not equal sign Non-equation &ne; &#8800; U+2260 Spaced
Approximate sign Approximation &asymp; &#8776; U+2248 Spaced
Less than sign Inequation < &lt; &#60; U+3C Spaced
Less than or equal to Inequation &le; &#8804; U+2264 Spaced
Greater than sign Inequation > &gt; &#62; U+3E Spaced
Greater than or equal to Inequation &ge; &#8805; U+2265 Spaced

## Geographical coordinates

Shortcuts:
WP:Coordinates
MOS:COORDS
For draft guidance on, and examples of, coordinates for linear features, see Wikipedia:WikiProject Geographical coordinates/Linear.
Quick guide:
Quick how tov · d · e
To add 57°18′22.5″N 4°27′32.7″W﻿ / ﻿57.30625°N 4.459083°W to the top of an article, use {{Coord}}, thus:
{{Coord|57|18|22.5|N|4|27|32.7|W|display=title}}

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

To add 44°06′43″N 87°54′47″W﻿ / ﻿44.112°N 87.913°W to the top of an article, use either
{{Coord|44.112|N|87.913|W|display=title}}

or

{{Coord|44.112|-87.913|display=title}}

These coordinates are in decimal degrees.

• Degrees, minutes and seconds must be separated by a pipe ("|").
• Map datum should be WGS84.
• Avoid excessive precision (0.0001° is <11 m, 1″ is <31 m).
• Latitude (N/S) must appear before longitude (E/W).
Optional coordinate parameters follow the longitude and are separated by an underscore ("_"):
• dim: dim:N (viewing diameter in metres)
• region: region:R (ISO 3166-1 alpha-2 or ISO 3166-2 code)
• type: type:T (landmark or city(30,000), for example)

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 in the title 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}}
• For full detail, refer to {{Coord/doc}}.
• Additional guidance is available: obtaining coordinates, converting coordinates

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.

Two types of template are available:

• {{coord}}, which has replaced the coor family (and combined their functionality), offers users a choice of display format through user styles, emits a Geo microformat, and is supported by Google Earth.
• Infoboxes such as {{Infobox settlement}}

Depending on the form of the coordinates, the following formats are available.

For just degrees (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, seconds, listed in sequence
• N/S is either N or S, depending on which hemisphere, and
• E/W is either E or W, depending on which hemisphere
• negative values may be used in lieu of S and W

For example:

The city of Oslo, located at 59° 55′ N, 10° 44′ E, enter:

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

A country, like Botswana, less precision is appropriate:

{{coord|22|S|24|E}} — which becomes 22°S 24°E﻿ / ﻿22°S 24°E

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 / ﻿33.94°N 118.4°W

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

Increasing or decreasing the number of decimal places can control the precision. Trailing zeroes should be included.

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 specification of attributes, such as type, region and scale.

When you have added 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 variables for coordinates: lat_d, lat_m, lat_s, lat_NS, long_d, long_m, long_s, long_EW.

## Notes

1. ^ Wikipedia:Requests for arbitration/Jguk#Principles, Wikipedia:Requests for arbitration/jguk 2#Principles, and Wikipedia:Requests for arbitration/Sortan#Principles
2. ^ This change was made on 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
3. ^ Some editors hold strong views for or against metrication in the UK. If a disagreement arises with respect to the main units used in a UK-related article, discuss the matter on the article talk-page and/or at MOSNUM talk. If consensus cannot be reached, refer to historically stable versions of the article and retain the units used in these (usually imperial units) as the main units. Note the style guides of British publications such as Times Online (under "Metric").
4. ^ This definition is consistent with all units of measure mentioned in the 8th edition of the SI brochure and with all units of measure catalogued in EU directive 80/181/EEC

Wikimedia Foundation. 2010.

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