Wikipedia:Manual of Style/Dates and numbers

"WP:DATE" redirects here. For the other guideline, see Wikipedia:Avoid statements that will date quickly.

This part of the Manual of Style aims to achieve consistency in the use and formatting of dates and numbers in Wikipedia articles. Consistent standards make articles easier to read, write and edit. 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.

In June 2005, the Arbitration Committee ruled that when either of two styles is acceptable, it is inappropriate for an editor to change an article from one style to another unless there is a substantial reason to do so. Edit warring over optional styles is unacceptable. If an article has been stable in a given style, it should not be converted without a style-independent reason. Where in doubt, defer to the style used by the first major contributor.

Non-breaking spaces

• In compound items in which numerical and non-numerical elements are separated by a space, non-breaking spaces are recommended to avoid the displacement of those elements at the end of a line.
• Non-breaking spaces are produced by keying in the HTML code   instead of a normal space; thus, 19 kg yields a non-breaking 19 kg.
• Non-breaking spaces can also be produced by using the {{nowrap}} template; thus, {{nowrap|4:40 pm}} produces a non-breaking 4:40 pm.

Chronological items

Precise language

Avoid statements that will date quickly, except on pages that are regularly refactored, such as those that cover current events. Avoid such items as recently and soon (unless their meaning is clear in a storyline), currently (except on rare occasions when it is not redundant), and is soon to be superseded. Instead, use either:

• more precise items (since the start of 2005; during the 1990s; is expected to be superseded by 2008); or
• an as of phrase (as of August 2007), which is a signal to readers of the time-dependence of the statement, and to later editors of the need to update the statement (see As of).

Times

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

• 12-hour clock times end with dotted or undotted lower-case a.m. or p.m., or am or pm, which are spaced (2:30 p.m. or 2:30 pm, not 2:30p.m. or 2:30pm). Noon and midnight are used 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 this is clear from the context.
• 24-hour clock times have no a.m., p.m., noon or midnight suffix. Discretion may be used as to whether the hour has a leading zero (08:15 or 8:15). 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.

Dates

• Wikipedia does not use ordinal suffixes or articles, or put a comma between month and year.

Incorrect:	June 25th, 25th June, the 25th of June
Correct:	14 February, February 14
Incorrect:	October, 1976
Correct:	October 1976

• Date ranges are preferably given with minimal repetition (5–7 January 1979; September 21–29, 2002), using an unspaced en dash. If the autoformatting function is used, the opening and closing dates of the range must be given in full (see Autoformatting and linking) and be separated by a spaced en dash.
• Rarely, 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); this cannot be done using the autoformatting function.
• Yearless dates (5 March, March 5) can be ambiguous. Include the year if the meaning is unclear. There is no such ambiguity with recurring events, such as "January 1 is New Year's Day".
• ISO 8601 dates (1976-05-12) are uncommon in English prose, and are generally not used in Wikipedia. However, they may be useful in long lists and tables for conciseness and ease of comparison.

Dates of birth and death

At the start of an article on a person, his or her dates of birth and death are provided. For example: “Charles Darwin (12 February 1809 – 19 April 1882) was a British ...”

• Locations of birth and death are given subsequently rather than being entangled with the dates.
• When only the years are known: Socrates (470–399 BC) (or “BCE”) was ...”
• For a person still living: “Serena Williams (born September 26 1981) ...”, not “(September 26 1981–) ...”
• When the date of birth is unknown: “Offa (died 26 July 796) ...”
• When the date of birth is known only approximately: “Genghis Khan (c. 1162 – August 18, 1227) ...”
• When the dates of both birth and death are known only approximately: “Dionysius Exiguus (c. 470 – c. 540) ...”
• When the date of death is unknown, but the person is certainly now dead: “Robert Menli Lyon (born 1789, date of death unknown) ...”
• When only the dates of the person's reign are known, and only approximately: “Rameses III (reigned c. 1180 BCE – c. 1150 BCE) ...”
• When the person is known to have been alive (flourishing) at certain dates, “[[floruit|fl.]]” is used to link to floruit, in case the meaning is not familiar: “Osmund (fl. 760–72) ...”
• When the person is known to have been alive as early as about 660, and to have died in 685: “Aethelwalh (fl. c. 660–85) ...”.

Longer periods

• Months are expressed as whole words (February, not 2), except in the ISO 8601 format. Abbreviations such as Feb 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. Because the seasons are reversed in each hemisphere—while areas near the equator tend to have just wet and dry seasons—neutral wording may be preferable (“in early 1990”, “in the second quarter of 2003”, “around September”). Consider using a date or month rather than a season, where there is no substantive reason to refer to a season, such as in the autumn harvest. Seasons are normally spelled with a lower-case initial.
• Years

• Years are normally expressed in digits; a comma is not used in four-digit years (1988, not 1,988).
• Avoid inserting the words the year before the digits (1995, not the year 1995), unless the meaning would otherwise be unclear.
• Either CE and BCE or AD and BC can be used—spaced, undotted and upper-case—to specify the era. Be consistent within the article. AD appears before or after a year (AD 1066, 1066 AD); the other abbreviations appear after (1066 CE, 3700 BCE, 3700 BC). The absence of such an abbreviation indicates the default, CE or AD. It is inappropriate for a Wikipedia editor to change from one style to another unless there is a substantive reason.
• Year ranges, like all ranges, are separated by an en dash (do not use a hyphen or slash: 2005–08, not 2005-08 or 2005/08). A closing CE/AD year is normally written with two digits (1881–86) unless it is in a different century from that of the opening year (1881–1986). The full closing year is acceptable, but abbreviating it to a single digit (1881–6) or three digits (1881–886) is not. A closing BCE or BC year is given in full (2590–2550 BCE). While one era signifier at the end of a date range still 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 – 29 AD).
• A slash may be used to indicate regular defined yearly periods that do not coincide with calendar years (the financial year 1993/94).
• Abbreviations indicating long periods of time ago—such as BP (before present), Ma and mya (million years ago), and Ga (billion years ago)—are spelled out on first occurrence.
• To indicate about, c. and ca. are preferred to circa or a question mark, and are spaced (c. 1291).

• Decades contain no apostrophe (the 1980s, not the 1980’s); the two-digit form is used only where the century is clear (the ’80s or the 80s).
• Centuries and milliennia

• There was no year 0. Thus, the first century CE was 1–100 AD, the 17th century AD was 1601–1700 CE, and the second millienium AD/CE was 1001–2000; the first century BCE was 100–1 BC; the 17th century BC was 1700–1601 BCE, and the second millennium BCE was 2000–1001 BC. Choose either the BC/AD or the BCE/CE system, but not both in the same article.
• Use numerals for centuries (the 17th century), except at the beginning of a sentence; do not capitalize century.
• The 1700s refers to a decade, not a century.

Calendars

See also: Old Style and New Style dates

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 1582-10-15 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 Gregorian 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 1752-09-14, and Russia from 1918-02-14 (see the Gregorian calendar article).

The dating method used in a Wikipedia article 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 is 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 stated.

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

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 United States, 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.

Autoformatting and linking

• Full dates, and days and months, are normally autoformatted, by inserting double square-brackets, as for linking. This instructs the WikiMedia software to format the item according to the date preferences chosen by registered users. It works only for users who are registered, and for all others will be displayed as entered.
• Do not autoformat dates that are:
  • in article and section headings,
  • on disambiguation pages,
  • within quotations (unless the original text was wikilinked).
  • in date ranges (see below).
• The autoformatting mechanism will not accept date ranges (December 13–17, 1951) or slashes (the night of 30/31 May), which must be input without using the function. Thus:
  • either [[January 15]] or [[15 January]] will be rendered as either January 15 or 15 January, according to a registered user's set preferences; and
  • [[January 15]], [[2001]] (US editors), [[15 January]] [[2001]] (others), [[2001-01-15]] (ISO), or [[2001 January 15]] will be rendered as January 15, 2001, 15 January 2001, 2001-01-15, or 2001 January 15, according to a registered user's set preferences.
• Wikipedia has articles on days of the year, years, decades, centuries and millennia. Link to one of these pages only if it is likely to deepen readers' understanding of a topic. Piped links to pages that are more focused on a topic are possible ([[1997 in South African sport|1997]]), but cannot be used in full dates, where they break the date-linking function.

Numbers

Spelling out numbers

General rule

• In the body of an article, single-digit whole numbers (from zero to nine) are spelled out; numbers of more than one digit are generally rendered as digits, but may be spelled out if they are expressed in one or two words (sixteen, eighty-four, two hundred and 3.75, 544, 21 million).

Exceptions

• 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.). Spell them out in historical references such as Seventh of March speech and Fifth of November.
• Numbers that open a sentence are spelled out; alternatively, the sentence can be recast so that the number is not in first position.
• In tables and infoboxes, all numbers are expressed as numerals.
• Within a context or a list, style should be consistent (either “There were 5 cats and 32 dogs” or “There were five cats and thirty-two dogs”, not “There were five cats and 32 dogs”).
• On rare occasions when digits may cause confusion, spell out the number (thirty-six 6.4-inch rifled guns, not 36 6.4-inch rifled guns).
• Fractions are normally spelled out; use the fraction form if they occur in a percentage or with an abbreviated unit (⅛ mm, but never an eighth of a mm) or they are mixed with whole numerals.
• Ordinal numbers are spelled out using the same rules as for cardinal numbers. The exception is single-digit ordinals for centuries, which may be expressed in digits (the 5th century CE). The ordinal suffix (e.g., th) is not superscripted (23rd and 496th, not 23^rd and 496^th).
• Proper names and formal numerical designations comply with common usage (Chanel No. 5, 4 Main Street, 1-Naphthylamine, Channel 6). This is the case even where it causes a numeral to open a sentence, although this is usually avoided by rewording.
• The numeral and the spelled-out number can have different meanings, as in these two phrases:
  • “Every number except one”, in which one refers to the number of exceptions (which could be, for example, the number 42); and
  • “Every number except 1”, in which the specific number 1 is excluded.

Hyphenation

• Spelled-out two-word numbers from 21 to 99 are hyphenated (fifty-six), as are fractions (seven-eighths). Do not hyphenate other multi-word numbers (five hundred, not five-hundred).

Large numbers

See also Magnitude prefixes, Order of magnitude and Long and short scales.

• Commas are used to break the sequence every three places left of the decimal point; a space is never used in this role (2,900,000, not 2 900 000).
• Large rounded numbers are generally assumed to be approximations; only where the approximation could be misleading is it necessary to qualify with about or a similar term.
• Avoid overly precise values where they are unlikely to be stable or accurate, or where the precision is unnecessary in the context (“The speed of light in a vacuum is 299,792,458 metres per second” is probably appropriate, but “The distance from the Earth to the Sun is 149,014,769 kilometres” and “The population of Cape Town is 2,968,790” would usually not be, because both values are unstable at that level of precision, and readers are unlikely to care in the context.)
• Scientific notation (5.8 × 10⁷) is preferred in scientific contexts.
• Where values in the millions occur a number of times through an article, upper-case M may be used for million, unspaced, after spelling out the first occurrence. (“She bequeathed her fortune of £100 million unequally: her eldest daughter received £70M, her husband £18M, and her three sons each just £4M each.”)
• Billion is understood as 10⁹. After the first occurrence in an article, billion may be abbreviated to unspaced bn ($35bn).

Decimal points

• A decimal point is used between the integral and the fractional parts of a decimal; a comma is never used in this role (6.57, not 6,57).
• Numerals to the right of the decimal are not separated every three decimal places, with spaces, commas or otherwise (0.2495929, not 0.249 592 9).
• 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”).
• Numbers between minus one and plus one require a leading zero (0.02, not .02); exceptions are performance averages in sports where a leading zero is not commonly used, and commonly used terms such as .22 caliber.

Percentages

• Percent or per cent are 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 are preferably 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 ("made the commission larger by half."). Percentage point should not be confused with basis point, which is a hundredth of a percentage point.

Natural numbers

The set of natural numbers has two common meanings: {0,1,2,3,…}, which may also be called non-negative integers, and {1,2,3,…}, which may also be called positive integers. Use the sense appropriate to the field to which the subject of the article belongs if the field has a preferred convention. If the sense is unclear, and if it is important whether or not zero is included, consider using one of the alternative phrases rather than natural numbers if the context permits.

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 _and).
• 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–Z for digits from 10 up to 35 (0x5AB3).

Units of measurement

Which system to use

• For US-related articles, the main units are US units; for example, 10 miles (16 km).
• For UK-related articles, the main units are metric except for fields in which imperial are still officially used, such as street traffic.
• For other country-related articles, the main units are metric; for example, 16 kilometres (10 mi).
• American English spells metric units with final -er (kilometer); in all other varieties of English, including Canadian English, -re is used (kilometre).
• In scientific articles, SI units are the main units, unless there are historical or pragmatic reasons not to do so (for example, Hubble’s constant should be quoted in its most common unit of (km/s)/Mpc rather than its SI unit of s⁻¹). Many scientific articles use natural units, such as the light second or Planck length, rather than a conventional unit, SI or otherwise.
• If editors cannot agree on the sequence of units, put the source value first and the converted value second. If the choice of units is arbitrary, use SI units as the main unit, with converted units in parentheses.

Conversions

• Conversions to and from metric and US units are generally provided. There are exceptions, including:
  • scientific articles where there is consensus among the contributors not to convert the metric units, in which case the first occurrence of each unit should be linked;
  • where inserting a conversion would make a common expression awkward (“The four-minute mile”).
  • in topics such as the history of maritime law in which imperial units (for example, miles and nautical miles) are part of the subject, it is useful to provide metric conversions, but excessive to convert exactly the same unit and value every time it occurs.
• In the main text, spell out the main units and use unit symbols or abbreviations for conversions in parentheses; for example, “a pipe 100 millimetres (4 in) in diameter and 16 kilometres (10 mi) long” or “a pipe 4 inches (100 mm) in diameter and 10 miles (16 km) long”. The exception is that where there is consensus to do so, the main units may also be abbreviated in the main text after the first occurrence.
• Converted values should use a level of precision similar to that of the source value; for example, “the Moon is 380,000 kilometres (240,000 mi) from Earth”, not “(236,121 mi)”. The exception is small numbers, which may need to be converted to a greater level of precision where rounding would be a significant distortion; for example, one mile (1.6 km), not one mile (2 km).
• {{Convert}} or unit-specific templates from Category:Conversion templates can be used to convert and format many common units in accordance with this manual of style.
• In a direct quotation:
  • conversions required for units cited within direct quotations should appear within square brackets in the quote;
  • if the text contains an obscure use of units (e.g., five million board feet of lumber), annotate it with a footnote that provides standard modern units, rather than changing the text of the quotation.
• Where footnoting or citing sources for values and units, identify both the source and the original units.

Unit symbols and abbreviations

• Standard abbreviations and symbols for units are undotted. For example, m for meter and kg for kilogram (not m. or kg.), in for inch (not in., " or ″), ft for foot (not ft., ' or ′) and lb for pound (not lb. or #).
• The degree symbol is °. Using any other symbol (e.g. masculine ordinal º or "ring above" ˚) for this purpose is incorrect.
• Do not append an s for the plurals of unit symbols (kg, km, in, lb, not kgs, kms, ins, lbs).
• Temperatures are always accompanied by °C for Celsius, °F for Fahrenheit, or K for Kelvin (35 °C, 5,000 K); these three symbols are always upper-case. For the first two, the unit is a degree; for the last, it is now normally the SI kelvin rather than degree Kelvin (i.e. do not use 5,000 °K)
• Values and unit symbols are spaced (25 kg, not 25kg). The exceptions are degrees, minutes and seconds for angles and coordinates (“the coordinate is 5° 24′ 21.12″ N”, “the pathways are at a 180° angle”, but “the average temperature is 18 °C”).
• Squared and cubic metric-symbols are always expressed with a superscript exponent (5 km², 2 cm³); squared US-unit abbreviations are rendered with sq, and cubic with cu (15 sq mi, 3 cu ft). A superscript exponent indicates that the unit is squared, not the unit and the quantity (3 meters squared is 9 square meters, or 9 m²; 8 miles squared is 64 square miles).
• In tables and infoboxes, use unit symbols and abbreviations; do not spell them out.
• Some different units share the same name. These examples show the need to be specific.
  • Use US or imperial gallon rather than just gallon.
  • Use nautical mile or statute mile rather than mile in nautical and aeronautical contexts.
  • Use long ton or short ton rather than just ton (the metric unit—the tonne—is also known as the metric ton).
• Ranges are preferably formatted with one rather than two unit signifiers (5.9–6.3 kg, not 5.9 kg – 6.3 kg).

Unnecessary vagueness

Use accurate measurements whenever possible.

Vague:	The wallaby is small.
Precise:	The average male wallaby is 1.6 metres (63 in) from head to tail.
Vague:	Prochlorococcus marinus is a tiny cyanobacterium.
Precise:	The cyanobacterium Prochlorococcus marinus is 0.5 to 0.8 micrometres across.
Vague:	The large herd of dugong stretched a long way down the coast.
Precise:	The dugong swam down the coast in a herd 5 kilometres (3 mi) long and 300 metres (1000 ft) wide.

Currencies

See also: WikiProject Numismatics: Article titles

Which one to use

• In country-specific articles, such as Economy of Australia, use the currency of the country.
• In non-country-specific articles such as Wealth, use US dollars (US$123).
• If there is no common English abbreviation or symbol, use the ISO 4217 standard.

Formatting

• Fully identify a currency on its first appearance (AU$52); subsequent occurrences are normally given without the country identification (just $88), unless this would be unclear. The exception to this is in articles related entirely to the US and the UK, in which the first occurrence may also be shortened ($34 and £22, respectively), unless this would be unclear. Avoid over-identifying currencies that cannot be ambiguous; e.g. do not place EU or a similar prefix before the € sign.
• Do not place a currency symbol after the value (123$, 123£), unless the symbol is normally written thus. Likewise, 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).
• Ranges are preferably formatted 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 euro or the US dollar. Conversions should be in parentheses after the original currency, with the year given as a rough point of reference; for example, “1,000 Swiss francs (US$763 in 2005)”, rounding to the nearest whole unit.
• Consider linking the first occurrence of a symbol for lesser-known currencies (₮146); it is generally unnecessary to link the symbols of well-known currencies.

Common mathematical symbols

See also: Manual of Style (mathematics).

• For a negative sign or subtraction operator, use a minus sign (−), input by clicking on it in the insert box beneath the edit window or by keying in −), or an en dash (see En dashes); do not use a hyphen, unless writing code.
• For a multiplication sign, use ×, which is input by clicking on it in the edit toolbox under the edit window or by keying in × (however, the letter ex is accepted as a substitute for "by" in such terms as "4x4").
• The following signs are spaced on both sides:
  • plus, minus, plus or minus (as operators): + − ±
  • multiplication and division: × ÷
  • equals, does not equal, is approximately equal to: = ≠ ≈
  • is less than, is less than or equal to, is greater than, is greater than or equal to: < ≤ > ≥

Magnitude prefixes

Binary prefixes

Multiple-byte units
Decimal Value Metric 1000 kB kilobyte 10002 MB megabyte 10003 GB gigabyte 10004 TB terabyte 10005 PB petabyte 10006 EB exabyte 10007 ZB zettabyte 10008 YB yottabyte 10009 RB ronnabyte 100010 QB quettabyte	Binary Value IEC Memory 1024 KiB kibibyte KB kilobyte 10242 MiB mebibyte MB megabyte 10243 GiB gibibyte GB gigabyte 10244 TiB tebibyte TB terabyte 10245 PiB pebibyte — 10246 EiB exbibyte — 10247 ZiB zebibyte — 10248 YiB yobibyte — — —
Orders of magnitude of data

In computing, where binary numbers (powers of 2) are often more useful than decimal (powers of ten), the de facto standard for binary prefixes and symbols (collectively, "units") is to use kilo-, mega-, giga-, with symbols K, M, G, where each successive prefix is multiplied by 1024 (2¹⁰) rather than SI's 1000 (10³). To attempt to resolve this ambiguity the IEC introduced new prefixes including kibi-, mebi-, gibi-, and symbols such as Ki, Mi, Gi in 1999 to specify binary multiples of a quantity. These replacements for the historical units have gained only limited acceptance outside the standards organizations. Most publications, computer manufacturers and software companies continue to use the historical binary units (KB, MB, GB).

There is no consensus to use the newer IEC-recommended prefixes in Wikipedia articles to represent binary units. There is consensus that editors should not change prefixes from one style to the other, especially if there is uncertainty as to which term is appropriate within the context—one must be certain whether "100 GB" means binary not decimal units in the material at hand before equating it with 100 GiB. When this is certain, the use of parentheses for IEC binary prefixes, for example, 256 KB (KiB) is acceptable, as is the use of footnotes to disambiguate prefixes. When in doubt, stay with established usage in the article, and follow the lead of the first major contributor. Prefixes in directly quoted passages are never changed; if explanation is necessary, use a more exact measurement in square brackets.

Measures that typically use decimal multiples:

• Capacities of hard disk drives and some other storage media
• Computer network and bus speeds

Measures that typically use binary multiples:

• Memory and cache sizes
• Some storage media

Orders of magnitude

See orders of magnitude and the talk page there for ongoing, possibly resolved debate on which style of exponent notation to use for large numbers.

Geographical coordinates

Geographical coordinates on Earth should be entered using a template to standardize the format and to provide a link to maps of the coordinates. As long as the templates are adhered to, the functions are performed automatically by a robot. Due to planned enhancements in functionality, this information is subject to change.

Two types of template are available:

• {{coor *}}, which is used in most articles and supported by all re-users, such as Google Earth and Wikipedia-World.
• {{coord}}, which combines the functionality of the coor family, offers users a choice of display format through user styles, emits a Geo microformat, and is supported by Google Earth.

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

For just degrees, use the d mode:

{{coor d|DD|N/S|DD|E/W|}} or

{{coord|dd|N/S|dd|E/W}}

For degrees/minutes, use the dm mode:

{{coor dm|DD|MM|N/S|DD|MM|E/W|}} or

{{coord|dd|mm|N/S|dd|mm|E/W}}

For degrees/minutes/seconds, use the dms mode:

{{coor dms|DD|MM|SS|N/S|DD|MM|SS|E/W|}} or

{{coord|dd|mm|ss|N/S|dd|mm|ss|E/W}}

where:

• latitude and longitude can be signified by decimal values in degrees
• 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

For example:

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

{{coor dm|59|55|N|10|44|E|}} or

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

for a country, like Botswana, less precision is appropriate:

{{coor d|22|S|24|E|}} or

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

for higher levels of precision, use the dms mode:

{{coor dms|33|56|24|N|118|24|00|W|}} or

{{coord|33|56|24|N|118|24|00|W}} — which becomes 33°56′24″N 118°24′00″W

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

• degrees can be specified with decimals, in d mode
• minutes can be specified with decimals, in dm mode
• seconds can be specified with decimals, in dms mode

Example:

{{coor d|33.94|S|118.40|W|}} or

{{coord|33.94|S|118.40|W}} or

{{coord|33.94|-118.40}}

The second and third examples become 33.94°N 118.40°W / 33.94; -118.40. The precision can be controlled by increasing or decreasing the number of decimal places. Trailing zeroes should be included.

The final field, following the E/W, is available for specification of attributes, such as type, region and scale. For more information, see the geographical coordinates WikiProject.

Templates other than {{coor *}} or {{coord}} should use the following variables for coordinates: lat_d, lat_m, lat_s, lat_NS, long_d, long_m, long_s, long_EW.

See also

• For page naming specifics, see Wikipedia:Naming conventions (numbers and dates).
• m:Help:Date formatting feature at Meta
• Wikipedia:Only make links that are relevant to the context#Dates