Wikipedia:Overview of date formatting guidelines
 | This is an essay. It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints. |
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 among these provisions can be summarised as follows:
- Consistency (MOS:DATEUNIFY): Each article should use either DMY or MDY consistently, except that in references, access/archive dates (and in some cases publication dates) may use YMD.
- Strong national ties to a topic (MOS:DATETIES): Articles on topics with strong ties to a particular English-speaking nation should generally use the date format most commonly used in that nation. This generally means:
- Articles on US topics use MDY, 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 necessarily use DMY, even though DMY 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 with any guidelines, occasional exceptions will apply. If you believe there are good reasons to diverge from the guidelines in a particular case, use common sense and achieve consensus on your proposal with other editors on the article's talk page.
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.