Editing Calendar date (section)

==Date format==
{{See also|Date format by country}}

[[File:Date format by country 3.svg|thumb|center|upright=3.2|{{legend|#0860a6|Day-Month-Year}} {{legend|#feb930|Year-Month-Day}} {{legend|#fd489d|Month-Day-Year}} {{legend striped|#0860a6|#feb930|DMY and YMD|up=yes}} {{legend striped|#0860a6|#fd489d|DMY and MDY|up=yes}} {{legend striped|#fd489d|#feb930|MDY and YMD|up=yes}} {{legend|#353535|MDY, DMY, and YMD}}]]

There is a large variety of formats for dates in use, which differ in the order of date components. These variations use the sample date of 31 May 2006: (e.g. 31/05/2006, 05/31/2006, 2006/05/31), component separators (e.g. 31.05.2006, 31/05/2006, 31-05-2006), whether leading zeros are included (e.g. 31/5/2006 vs. 31/05/2006), whether all four digits of the year are written (e.g., 31.05.2006 vs. 31.05.06), and whether the month is represented in [[Arabic numerals|Arabic]] or [[Roman numerals]] or by name  (e.g. 31.05.2006, 31.V.2006 vs. 31 May 2006).

===Gregorian, day–month–year (DMY) <span id="DMY date"></span> ===
[[File:Příležitostné razítko pof. PR7, 13.06.1939.jpg|thumb|Postal mark of Czechoslovakia dated 13 June 1939]]
This [[Endianness|little-endian]] sequence is used by a majority of the world and is the preferred form by the [[United Nations]] when writing the full date format in official documents. This date format originates from the custom of writing the date as "the Nth day of [month] in the year of our Lord [year]" in Western religious and legal documents. The format has shortened over time but the order of the elements has remained constant. The following examples use the date of 9 November 2006. (With the years 2000–2009, care must be taken to ensure that [[Year 2000 problem|two digit years do not intend to be 1900–1909 or other similar years]].) The dots have a function of [[ordinal dot]].

* "9 November 2006" or "9. November 2006" (the latter is common in [[German language|German]]-speaking regions)
* 9/11/2006 or 09/11/2006
* 09.11.2006 or 9.11.2006
* 9. 11. 2006
* 9-11-2006 or 09-11-2006
* 09-Nov-2006
* 09Nov06 – Used, including in the U.S., where space needs to be saved by skipping [[punctuation]] (often seen on the [[dateline]] of Internet news articles).
* [The] 9th [of] November 2006 – 'The' and 'of' are often spoken but generally omitted in all but the most formal writing such as legal documents.
* 09/Nov/2006 – used in the [[Common Log Format]]
* Thursday, 9 November 2006
* 9/xi/06, 9.xi.06, 9-xi.06, 9/xi-06, 9.XI.2006, 9. XI. 2006 or 9 XI 2006 (using the [[Roman numerals|Roman numeral]] for the month) – In the past, this was a common and typical way of distinguishing day from month and was widely used in many countries, but recently this practice has been affected by the general retreat from the use of Roman numerals.{{cn|date=August 2021}} This is usually confined to handwriting only and is not put into any form of print.{{Citation needed|date=August 2021}} It is associated with a number of schools and universities. It has also been used by the Vatican as an alternative to using months named after Roman deities.{{cn|date=August 2021}} It is used on Canadian postmarks as a [[bilingual]] form of the month. It was also commonly used in the [[Soviet Union]], in both handwriting and print.
* 9 November 2006 [[Common Era|CE]] or 9 November 2006 [[Anno Domini|AD]]

===Gregorian, year–month–day (YMD) <span id="YMD date"></span>===
<!--[[YMD]] and [[YMD date]] redirect here-->
{{Redirect|YMD}}
In this format, the most significant data item is written before lesser data items i.e. the year before the month before the day. It is consistent with the [[Endianness|big-endianness]] of the [[Hindu–Arabic numeral system]], which progresses from the highest to the lowest order magnitude. That is, using this format textual orderings and chronological orderings are identical. This form is standard in East Asia, Iran, Lithuania, Hungary, and Sweden; and some other countries to a limited extent.

Examples for the 9th of November 2003:
*2003-11-09: the standard Internet date/time format,<ref>[http://www.w3.org/TR/NOTE-datetime W3C Date and Time Formats] Internet date/time format<!-- retrieved 23 September --></ref> a profile of the international standard [[ISO 8601]], orders the components of a date like this, and additionally uses leading zeros, for example, 1996-05-01, to be easily read and sorted by computers. It is used with [[UTC]] in RFC 3339. This format is also favored in certain [[Asia]]n countries, mainly [[East Asian]] countries, as well as in some European countries. The big-endian convention is also frequently used in [[Canada]], but all three conventions are used there (both endians and the American MMDDYYYY format are allowed on Canadian bank cheques provided that the layout of the cheque makes it clear which style is to be used).<ref>{{cite web|url=http://www.cdnpay.ca/news/new_cheque_specs.asp |title=Canadian Payments Association – Specifications for Imageable Cheques and Other Payment Items |url-status=dead |archive-date=6 July 2010 |archive-url=https://web.archive.org/web/20100706223651/http://www.cdnpay.ca/faqs/new_specifications.asp |date=February 3, 2009 |quote=Adoption of a numeric date field in one of three specified formats (YYYYMMDD, MMDDYYYY or DDMMYYYY. It is essential that field indicators be printed below the date field to indicate which format is being used.}}</ref>
* 2003 November 9
* 2003Nov9 or 2003Nov09
* 2003-Nov-9 or 2003-Nov-09
* 2003-Nov-9, Sunday
* 2003. {{sic|hide=y|no|vember}} 9. – The official format in [[Hungary]], point after year and day, month name with small initial. Following shorter formats also can be used: 2003. {{sic|hide=y|nov}}. 9., 2003. 11. 9., 2003. XI. 9.
* 2003.11.9 using [[Full stop|dots]] and no leading zeros, common in [[China]].
* 2003.11.09
* 2003/11/09 using [[slash (punctuation)|slash]]es and leading zeros, common in [[Japan]] on the Internet.
* 2003/11/9
* 03/11/09
* 20031109 : the "basic format" profile of ISO 8601, an 8-digit number providing [[monotonic]] date codes, common in computing and increasingly used in dated computer file names. It is used in the standard [[iCalendar]] file format defined in RFC 5545. A big advantage of the ISO 8601 "basic format" is that a simple textual sort is equivalent to a sort by date.

It is also extended through the universal big-endian format clock time: 2003 November 9, 18h 14m 12s, or 2003/11/9/18:14:12 or (ISO 8601) 2003-11-09T18:14:12.

===Gregorian, month–day–year (MDY)<span id="MDY date"></span>===
{{Use American English|date=April 2020}}
<!--[[MDY date]] redirects here-->
{{See also|Date and time notation in the United States|Date and time notation in Canada}}
This sequence is used primarily in the [[Philippines]] and the [[United States]]. It is also used to varying extents in [[Canada]] (though never in [[Quebec]]).<ref>{{cite news |last=Sanderson |first=Blair |title=Proposed legislation aims to settle date debate |url=https://www.cbc.ca/news/canada/proposed-legislation-aims-to-settle-date-debate-1.3407640 |access-date=25 September 2017 |work=CBC News |date=18 January 2016}}</ref> This date format was commonly used alongside the little-endian form in the United Kingdom until the mid-20th century and can be found in both defunct and modern print media such as the ''[[London Gazette]]'' and ''[[The Times]]'', respectively. This format was also commonly used by several English-language print media in many former British colonies and also one of two formats commonly used in India during [[British Raj]] era until the mid-20th century. 

* Thursday, November 9, 2006
* November 9, 2006
* Nov 9, 2006
* Nov-9-2006
* Nov-09-2006
* 11/9/2006 or 11/09/2006
* 11-09-2006 or 11-9-2006
* 11.09.2006 or 11.9.2006
* 11.09.06
* 11/09/06

Modern style guides recommend avoiding the use of the ordinal (e.g. 1st, 2nd, 3rd, 4th) form of numbers when the day follows the month (July 4 or July 4, 2024),<ref name="AP_style">{{cite report |author=Washington Journalism Education Association |date=February 21, 2014 |title=Associated Press Style 'Cheat Sheet' |url=https://wjea.org/wp-content/uploads/2014/02/WJEA-AP-Style-Cheat-Sheet.pdf |publisher=Washington Journalism Education Association |access-date=2024-06-15}}</ref><ref name="c455">{{cite web | title=Australian Government Style Manual: Dates and time | website=Australian Government | date=2020-12-31 | url=https://www.stylemanual.gov.au/grammar-punctuation-and-conventions/numbers-and-measurements/dates-and-time#follow_australian_conventions_for_dates | access-date=2024-06-16}}</ref> and that format is not included in [[ISO]] standards.<ref name="m820">{{cite web | title=SO/DIS 34000(en) Date and time — Concepts and vocabulary | website=ISO | url=https://www.iso.org/obp/ui/fr/#iso:std:iso:34000:dis:ed-1:v1:en:term:7.8 | access-date=2024-06-16}}</ref> The ordinal was common in the past and is still sometimes used ([the] 4th [of] July or [[Independence Day (United States)|July 4th]]).

===Gregorian, year–day–month (YDM)<span id="YDM date"></span>===
This date format is used in [[Kazakhstan]], [[Latvia]], [[Nepal]], and [[Turkmenistan]]. According to the official rules of documenting dates by governmental authorities,<ref>{{Cite web| url=http://adilet.zan.kz/kaz/docs/V1400010129 | publisher=Government of Kazakhstan (in Kazakh) | title=Official rules of documenting in governmental authorities}}</ref><!-- This document doesn't mention numerical formats (e.g. 2021.13.01 rather than 2021-01-13), and the all-numeric format DD.MM.YYYY is used in this Kazakh document. Localization databases like CLDR ignored it. --> the long date format in Kazakh is written in the year–day–month order, e.g. 2006 5 April ({{langx|kk|2006 жылғы 05 сәуір}}). However, both Latvia and Kazakhstan use the day-month-year format (DD.MM.YYYY or DD/MM/YYYY) for all-numeric dates.<ref>{{Cite web |title=Kā latviešu valodā pareizi rakstāms datums? |url=https://www.diena.lv/raksts/pasaule/krievija/ka-latviesu-valoda-pareizi-rakstams-datums-10007855 |access-date=2025-02-27 |website=www.diena.lv}}</ref><ref>{{Cite web |title=Статистическая карта амбулаторного пациента для консультативно-диагностических центров (поликлиник). Форма 025-9/у (утверждена приказом и.о. Министра здравоохранения Республики Казахстан от 8 июля 2005 года № 332) (утратила силу) |url=https://online.zakon.kz/Document/?doc_id=30548668 |access-date=2025-02-27 |website=Информационная система ПАРАГРАФ |language=ru}}</ref>

===Standards===
There are several standards that specify date formats:
* [[ISO 8601]] ''Data elements and interchange formats – Information interchange – Representation of dates and times'' specifies ''YYYY-MM-DD'' (the separators are optional, but only hyphens are allowed to be used), where all values are fixed length numeric, but also allows ''YYYY-DDD'', where ''DDD'' is the ordinal number of the day within the year, e.g. 2001–365.<ref>{{cite web| url = http://www.iso.org/iso/catalogue_detail?csnumber=40874| title = ISO 8601:2004 ''Data elements and interchange formats – Information interchange – Representation of dates and times''}}</ref>
* RFC 3339 ''Date and Time on the Internet: Timestamps'' specifies ''YYYY-MM-DD'', i.e. a particular subset of the options allowed by ISO 8601.<ref>{{Cite IETF |rfc=3339 |section=5.6 |title=Date and Time on the Internet: Timestamps |sectionname=5.6 Internet Date/Time Format}}</ref>
* [[RFC 5322]] ''Internet Message Format'' specifies ''day month year'' where ''day'' is one or two digits, ''month'' is a three letter month abbreviation, and ''year'' is four digits.<ref>{{Cite IETF |rfc=5322 |section=3.3 |title=Internet Message Format |sectionname=3.3 Date and Time Specification}}</ref>

===Difficulties===
[[File:Memorial to John Etty (18373251064).jpg|thumb|Memorial plaque to John Etty in [[All Saints' Church, North Street, York]], uses [[dual dating]] style to record his date of death as "28 of Jan: {{sfrac|170|8|9}}" ]]
Many numerical forms can create confusion when used in international correspondence, particularly when abbreviating the year to its final two digits, with no context. For example, "07/08/06" could refer to either 7 August 2006 or July 8, 2006 (or 1906, or the sixth year of any century), or 2007 August 6.

The date format of YYYY-MM-DD in ISO 8601, as well as other international standards, have been adopted for many applications for reasons including reducing transnational ambiguity and simplifying machine processing.<ref>{{Cite web |title=International standard date and time notation |url=https://fits.gsfc.nasa.gov/iso-time.html#:~:text=This%20standard%20notation%20helps%20to,traditional%20date%20and%20time%20notations. |access-date=2024-05-01 |website=fits.gsfc.nasa.gov}}</ref> 

An early U.S. [[Federal Information Processing Standard]] recommended 2-digit years. This is now widely recognized as extremely problematic, because of the [[year 2000 problem]]. Some U.S. government agencies now use ISO 8601 with 4-digit years.<ref>{{cite web |title=Date Format for Web site – Information Systems Department Release |date=2002-07-01 |website=Nye County, Nevada |url=http://www.nyecounty.net/iso8601.html |archive-url=https://web.archive.org/web/20080221020451/http://www.nyecounty.net/iso8601.html|archive-date=February 21, 2008}}</ref>{{bsn|reason=It is not clear at what point the piece is copied from elsewhere, so find the original -- possibly by Arthur David Olson at the tz nih archive.|date=November 2023}} 

When transitioning from one calendar or date notation to another, a format that includes both styles may be developed; for example [[Old Style and New Style dates]] in the transition from the Julian to the Gregorian calendar.<ref>{{cite web |last=Spathaky |first=Mike |url=https://www.cree.name/genuki/dates.htm |title=Old Style and New Style Dates and the change to the Gregorian Calendar |access-date=19 August 2023}}. "Before 1752, parish registers, in addition to a new year heading after 24th March showing, for example '1733', had another heading at the end of the following December indicating '1733/4'. This showed where the Historical Year 1734 started even though the Civil Year 1733 continued until 24th March. ... We as historians have no excuse for creating ambiguity and must keep to the notation described above in one of its forms. It is no good writing simply 20th January 1745, for a reader is left wondering whether we have used the Civil or the Historical Year. The date should either be written 20th January 1745 OS (if indeed it was Old Style) or as 20th January 1745/6. The hyphen (1745-6) is best avoided as it can be interpreted as indicating a period of time."</ref>