Template:Date/doc

Description
This template converts a date to one of the standard date formats used on the English Wikipedia. This template is probably best used internally in other templates.

Syntax
This template takes up to two parameters, both of which are optional:

  |  

For example,   produces.
 *   is an (optional) date to be formatted.
 * If no date is specified, the template emits the current date.
 * If a date is provided, but is not recognized as one, the text is just returned as is. Most dates will however be recognized as such, including all the formats typically used on Wikipedia. Numerous variations thereof are also supported, including abbreviated or lower case month names; genitive "st", "nd", "rd", "th"; extraneous white space; missing comma etc.
 * Notes:
 * Some dates are converted even if they are not real dates, and some dates are not converted even though they are real dates. See known issues below.
 * Only dates within the range January 1, 1000 and December 31, 9999 are supported. Dates with two digit dates will have unexpected results. Other dates outside the range 1000–9999 will be treated as if the second parameter were "none".


 *   controls the date format in which the result is to be emitted. Recognized values for the second parameter are:
 * none applies no formatting whatsoever
 * dmy gives d mmmm yyyy (eg 2011-12-25). This is the default format.
 * mdy gives mmmm d, yyyy (eg 2011-12-25)
 * ymd gives yyyy mmmm dd (eg 2011-12-25)
 * iso gives an ISO 8601 style yyyy-mm-dd (eg 2011-12-25)
 * If a date to be formatted is provided but no style is specified, the template emits a date in "d month yyyy" format, as it appears (for example) on discussion pages. When no date is specified, then the current date is emitted with no year, either in "d month" format for formatting style, or in "month d" format for formatting styles  ,   and.
 * Notes:
 * Although these are the four formats supported by MediaWiki's date autoformatting mechanism, only /  and  /  are in accordance with the English language Wikipedia's Manual of Style. The use of  /  (ISO 8601) format within article prose is expressly discouraged by the Manual of Style; this format should only be used in tables or lists.
 * In each case, the result is exactly the same as what would be emitted by MediaWiki's date autoformatting mechanism. However, dates are not manipulated by MediaWiki's date autoformatting mechanism even when linked. This permits dates to have a consistent appearance regardless of whether they are linked or not.

Other acceptable input
A wide variety of other input formats are handled correctly by the template:

Invalid input
Input strings that the template cannot format are returned unaltered. This includes strings containing characters such as square brackets, so any links will result in unformatted output.

Known issues

 * Out-of-range values are "fixed"
 * The PHP library that this template ultimately depends on converts out-of-range values to the next-best in-range values. As a result, some date-like values that are not actually valid dates get converted anyway. These include...
 * all dates with zero day-of-the-month. Such a "zero-th" day of a month gets converted into the last day of the previous month. For example,  results in  .  Similarly,   becomes.
 * all dates with day-number values that exceed the number of days in the specified month cause the date to be incremented into the next month. For example,  results in , since November has only 30 days.  Similarly,   results in  , since 2007 was not a leap year.  Note: Due to a parser peculiarity in the PHP library, 'December 32' and '32 December' are treated differently, and the latter results in an error (which causes this template to emit it unchanged), and only the former "overflows" into the next month.


 * Non-Gregorian dates are treated as Gregorian
 * The PHP library that this template ultimately depends on assumes that all dates, irrespective of context, are Gregorian calendar dates. Consequently:
 * some dates that would be valid in a non-Gregorian context are treated as out-of-range dates and converted to the next-best in-range values. For example,  results in   because – even though 30 February 1712 is a valid date in the Swedish calendar – February 1712 had only 29 days in the Gregorian calendar.
 * ten dates are not reformatted. These are 29 February & 1 March of the years 1000, 1100, 1300, 1400, 1500. The cause of this is the same as that of the Swedish 30 February 1712.
 * some dates that would not be valid in some contexts are converted normally. For example, 29 February 1912 or 1 February 1918 are not valid in a Russian context, but perfectly valid in the Gregorian one.

The ISO 8601 standard requires mutual agreement between those using the format to use years earlier than 1583. Since no agreement has been obtained from our readers, that format should not be used for such years, nor for any date not in the Gregorian calendar.
 * ISO 8601 format not suitable for years before 1583