Editing Help:CS1 errors (section)

==<span id="bad_date">Check date values in: |&lt;param1>=, |&lt;param2>=, ...</span>==
<section begin="bad_date_help_text" />{{help desk}}
{{plainlist}}
*{{#invoke:Cs1 documentation support|help_text_error_messages|err_bad_date|$1=<code class="cs1-code">{{pipe}}&lt;param1>=</code>, <code class="cs1-code">{{pipe}}&lt;param2>=</code>, ...}}
*{{#invoke:Cs1 documentation support|help_text_error_messages|err_bad_date|$1=<code class="cs1-code">{{pipe}}year=</code> / <code class="cs1-code">{{pipe}}date=</code> mismatch}}
{{endplainlist}}

When {{cs1}} and {{cs2}} templates contain date-holding parameters, an automated test is done to see if the dates are real dates that comply with a [[Help:Citation_Style_1#Date format compliance with Wikipedia's Manual of Style|subset of the date rules]] in  Wikipedia's Manual of Style, specifically checking for violations of [[Wikipedia:Manual of Style/Dates and numbers#Dates and years|MOS:DATEFORMAT]].

To resolve this error, ensure that the date is an actual date and that the date format follows the [[MOS:DATEFORMAT|Wikipedia Manual of Style's guidance on dates]] in the named parameter. See [[Help:CS1 errors#ExamplesOfUnacceptableDates|examples of unacceptable dates and how to fix them]], below.  Or, some conceptual issues to look for:
* impossible dates, such as 29 February 2011 (2011 was not a leap year)
* {{para|access-date}} must specify a day, not just a month or year
* {{para|archive-date}} must specify a whole date
* misplaced, incorrect, or extraneous punctuation
* misplaced, incorrect, or extraneous spacing
* extraneous text 
* hyphens or slashes instead of en dashes in date ranges (en dashes are required) 
* misspelling or improper capitalization (see [[MOS:ALLCAPS]] for more detail that is not in [[MOS:DATEFORMAT|Wikipedia Manual of Style's guidance on dates]])
* other unacceptable date formats listed in [[MOS:BADDATEFORMAT]]
* more than one date in a date-holding parameter
* days of the week (such as Monday, June 6 instead of June 6)
* years before 100 AD, including BCE/BC dates. Try using parameter {{para|orig-date}} instead. 

See [[Help:Citation_Style_1#CS1_compliance_with_Wikipedia.27s_Manual_of_Style|Help: Citation Style 1]] for information about limitations in the CS1 citation templates' handling of date formats. [[WP:DATERANGE|The MOS section on date ranges]] describes how to separate dates in a date range. Do not use <code>&amp;nbsp;</code>, <code>&amp;ndash;</code>, or {{tlx|spaced ndash}} as these corrupt the metadata. To add an en dash, use the [[Help:CharInsert#Insert|CharInsert]] edit tool or see [[Wikipedia:How to make dashes]]. You may also copy and paste this one: &ndash;. A bot is often able to correct the separator, provided the overall format is unambiguous.

Future dates in {{para|date}} in CS1|2 citations are limited to current year + 1; that is, for {{#time:Y}}, citation dates in {{#time:Y|now +1 year}} are acceptable but citation dates in {{#time:Y|now +2 year}} and beyond are not.

Dates prior to 1582 are treated as [[Julian calendar]] dates. Dates from 1582 onward are treated as [[Gregorian calendar]] dates. The Julian calendar was used in some places until approximately 1923. Three Julian calendar dates in the overlap period, 29 February in the years 1700, 1800, and 1900, will cause this error message because those years are not leap years in the Gregorian calendar.

The access date (in {{para|access-date}}) is checked to ensure that it contains a full date (day, month, and year) and is between 15 January 2001 (the founding date of Wikipedia) and today's date plus one day, because it represents the date that an editor viewed a web-based source to verify a statement on Wikipedia. Because editors may be in time zones that are one day ahead of the UTC date, one extra day is accepted.
 
Pages with this error are automatically placed in {{#invoke:cs1 documentation support|help_text_cats|err_bad_date|pages=yes}}.<ref group="lower-alpha" name="categories" /><section end="bad_date_help_text" />
{{anchor|Date Fix Table|Dates|DateFixTable}}
{{anchor|ExamplesOfUnacceptableDates}}
{| class="wikitable"
|+ Examples of unacceptable dates and how to fix them
|-
! Issue !! Unacceptable !! Acceptable
|-
| Hyphen in date range (use en dash) || {{para|plain=y|date|2002{{red|-}}2003}} || {{para|plain=y|date|2002{{green|–}}2003}}
|-
| Slash in date range (use en dash) || {{para|plain=y|date|2002{{red|/}}2003}} or {{para|plain=y|date|July{{red|/}}August 2003}}||{{para|plain=y|date|2002{{green|–}}2003}} or {{para|plain=y|date|July{{green|–}}August 2003}}
|-
| Hyphen in date range (use en dash) || {{para|plain=y|date|April{{red|-}}May 2004}} || {{para|plain=y|date|April{{green|–}}May 2004}}
|-
| Missing space around en dash for range of full dates || {{para|plain=y|date|April 2003{{red|–}}May 2004}} || {{para|plain=y|date|April 2003 {{green|–}} May 2004}}
|-
| Month capitalization || {{para|plain=y|date|28 {{red|f}}ebruary 1900}} || {{para|plain=y|date|28 {{green|F}}ebruary 1900}}
|-
| Month capitalization || {{para|plain=y|date|28 F{{red|EBRUARY}} 1900}} || {{para|plain=y|date|28 F{{green|ebruary}} 1900}}
|-
| Season capitalization || {{para|plain=y|date|{{red|s}}pring 2011}} || {{para|plain=y|date|{{green|S}}pring 2011}}
|-
| Future date (typo) || {{para|plain=y|date|2{{red|10}}2}} || {{para|plain=y|date|2{{green|01}}2}}
|-
| Access date in future (see note above) || {{para|plain=y|access-date|{{red|{{day+1|{{day+1}}}}, {{CURRENTYEAR}}}}}} || {{para|plain=y|access-date|{{Currentmonthday}}, {{CURRENTYEAR}}}}
|-
| Access date impossibly far in the past (typo) || {{para|plain=y|access-date|1 January 20{{red|01}}}} || {{para|plain=y|access-date|1 January 20{{green|10}}}}
|-
| Access date only specifies month || {{para|plain=y|access-date|{{red|January}} 2015}} || {{para|plain=y|access-date|{{green|12 January}} 2015}}
|-
| Ambiguous date range or year and month || {{para|plain=y|date|2002-{{red|03}}}} || {{plainlist|
* {{para|plain=y|date|2002–{{green|20}}03}}
* {{para|plain=y|date|{{green|March}} 2002}}}}
|-
| Bad abbreviation || {{para|plain=y|date|{{red|Febr.}} 28, 1900}} || {{plainlist|
* {{para|plain=y|date|{{green|Feb}} 28, 1900}}
* {{para|plain=y|date|{{green|February}} 28, 1900}}}}
|-
| Nonexistent date || {{para|plain=y|date|{{red|February 29, 1900}}}} ||
|-
| Undated || {{para|plain=y|date|{{red|Undated}}}} || {{para|plain=y|date|{{green|n.d.}}}}
|-
| Comma in month and year || {{para|plain=y|date|February{{red|,}} 1900}} || {{para|plain=y|date|February 1900}}
|-
| Comma in season || {{para|plain=y|date|Winter{{red|,}} 1900–1901}} || {{para|plain=y|date|Winter 1900–1901}}
|-
| Missing comma in format which requires it || {{para|plain=y|date|{{red|February 28 1900}}}} || {{para|plain=y|date|February 28{{green|,}} 1900}} or {{para|plain=y|date|28 February 1900}} or {{para|plain=y|date|1900-02-28}}
|-
| Non-date text || {{para|plain=y|date|2008{{red|, originally 2000}}}} || {{para|plain=y|date|2008}} {{green|{{para|plain=y|orig-date|2000}}}}
|-
| Zero-padding || {{para|plain=y|date|January {{red|04}}, 1987}} || {{para|plain=y|date|January {{green|4}}, 1987}}
|-
| Date with slashes || {{para|plain=y|date|12{{red|/}}6{{red|/}}87}} || {{para|plain=y|date|{{green|December 6, 19}}87}} or {{para|plain=y|date|{{green|6 December 19}}87}} or {{para|plain=y|date|{{green|1987-12-06}}}}<br/>or<br/>{{para|plain=y|date|{{green|12 June 19}}87}} or {{para|plain=y|date|{{green|June 12, 19}}87}} or {{para|plain=y|date|{{green|1987-06-12}}}}
|-
| Two-digit year || {{para|plain=y|date|{{red|87}}-12-06}} || {{para|plain=y|date|{{green|19}}87-12-06}}
|-
| One-digit month or day || {{para|plain=y|date|2007-{{red|3}}-{{red|6}}}} || {{para|plain=y|date|2007-{{green|03}}-{{green|06}}}}
|-
| Wikified date || {{para|plain=y|date|{{red|<nowiki>[[</nowiki>}}April 1{{red|<nowiki>]]</nowiki>}}, {{red|<nowiki>[[</nowiki>}}1999{{red|<nowiki>]]</nowiki>}} }} || {{para|plain=y|date|{{green|April 1, 1999}}}}
|-
| "mm-dd-yyyy" or "dd-mm-yyyy" date format || {{para|plain=y|date|{{red|07-12-}}2009}} || {{para|plain=y|date|{{green|7 December}} 2009}} or {{para|plain=y|date|{{green|12 July}} 2009}}<br />or<br />{{para|plain=y|date|{{green|July 12,}} 2009}} or {{para|plain=y|date|{{green|December 7,}} 2009}}<br />or <br />{{para|plain=y|date|2009-{{green|07-12}}}} or {{para|plain=y|date|2009-{{green|12-07}}}}
|-
| Quarters || {{para|plain=y|date|{{red|3Q}} 1984}} or {{para|plain=y|date|{{red|3rd Qtr.,}} 1984}} or {{para|plain=y|date|{{red|Third quarter}} 1984}} || {{para|plain=y|date|{{green|Third Quarter}} 1984}}
|-
| Named dates || {{para|plain=y|date|{{red|Xmas}} 1984}} or {{para|plain=y|date|{{red|christmas}} 1984}} || {{para|plain=y|date|{{green|Christmas}} 1984}}
|-
| Approximate or uncertain dates || {{para|plain=y|date|{{red|circa}} 1970}} or {{para|plain=y|date|{{red|<nowiki>{{circa}}</nowiki>}} 1970}} || {{para|plain=y|date|{{green|c.}} 1970}}
|-
|}