Wikipedia:Overview of date formatting guidelines
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MOS:DATEFORMAT sets out the three date formats acceptable for use in Wikipedia articles, namely:
- Day–month–year (DMY) format—e.g., 7 June 2025 or 7 Jun 2025;
- Month–day–year (MDY) format—e.g., June 7, 2025 or Jun 7, 2025;
- Year–month–day (YMD) format—e.g., 2025-06-07 (also called the "all-numeric" format; used only in places where space is limited—references, tables, infoboxes—and not in article text proper).
Which format should be used in a particular situation is controlled by the (somewhat confusing) interaction of three provisions: MOS:DATEUNIFY, MOS:DATETIES, and MOS:DATERET. The priority between these provisions can be summarised as follows:
- Consistency (MOS:DATEUNIFY): Each article should use either DMY or MDY format consistently, except access/archive dates (and in some cases publication dates) in references may use YMD-formatted dates.
- Strong national ties to a topic (MOS:DATETIES): Articles on topics with strong ties to a particular English-speaking country should generally use the date format most commonly used in that nation. This generally means:
- Articles on US topics use MDY format, except articles on modern US military topics use DMY in line with modern military usage;
- Articles on Canadian topics may use either DMY or MDY;
- Articles on topics relating to other English-speaking countries use DMY.
- There may be other exceptions for particular topic areas.
- Note that because this is the English language Wikipedia, MOS:DATETIES does not apply to topics related to non-English-speaking countries. For example, articles on French topics do not need to follow DMY format even though this is the predominant format in France.
- Retaining existing format (MOS:DATERET): If an article has evolved using predominantly one format, don't change it unless:
- to conform with strong national ties (in accordance with MOS:DATETIES, as discussed in 2 above); or
- there is consensus on the article's talk page otherwise (see below).
As is the case with any guidelines, occasional exceptions will apply. If there are good reasons to ignore the guidelines in particular cases, use common sense and discuss any proposed deviation from the guidelines on the relevant talk page for an article to reach consensus.
Caution should be used before making changes to the established date formats of existing articles, especially changes to multiple articles in a particular subject area. Consider whether the proposed change would improve Wikipedia and whether editors who have contributed to the articles on a particular subject may have reached a consensus to use a particular format. Some editors may revert changes to date formats that are made without prior discussion, even when those changes cite appropriate sections of the guidelines supporting them.