https://wiki.nichework.com/w/index.php?action=history&feed=atom&title=Template%3AIs_leap_year%2FdocTemplate:Is leap year/doc - Revision history2026-05-09T08:53:50ZRevision history for this page on the wikiMediaWiki 1.44.5https://wiki.nichework.com/w/index.php?title=Template:Is_leap_year/doc&diff=2831&oldid=prevMarkAHershberger: 1 revision imported2026-01-19T18:40:59Z<p>1 revision imported</p>
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<p><b>New page</b></p><div>{{Documentation subpage}}<br />
{{tsh|Ly|isLeapYear}}<br />
<!-- EDIT TEMPLATE DOCUMENTATION BELOW THIS LINE --><br />
<br />
=== Usage ===<br />
<br />
: {{Tlx|is leap year|''year''}}<br />
: ''year'' defaults to {{tld|CURRENTYEAR|}} ({{CURRENTYEAR}}). It must be specified in the Gregorian calendar, extended to all epochs using linear year numbering: use the [[proleptic Gregorian calendar]] in Christian Era before the change, and the astronomical year convention (using negative numbers, and year 0) in all years BC before the Christian era (there's a difference of 1 in absolute value).<br />
===Parameters===<br />
* ''Unnamed parameter'' The year to calculate with (default: {{CURRENTYEAR}})<br />
* {{para|yes}} What to output if it is a leap year (default : 1)<br />
* {{para|no}} What to output if it isn't a leap year (default: 0)<br />
=== Formula ===<br />
The template currently uses Wikimedia function time (#time). It is the same as if 4 mod year = 0 and 100 mod year ≠ 0, then not a leap year, unless 400 mod year = 0, then it is a leap year.<br />
<br />
=== Sanity check ===<br />
* {{tld|is leap year|2000|_show_result=y}}: 2000 AD is ''effectively'' a leap year ''(in both the Julian and Gregorian calendars)''.<br />
* {{tld|is leap year|502*4-8|_show_result=y}}: 2000 AD is ''effectively'' a leap year ''(in both the Julian and Gregorian calendars)''.<br />
* {{tld|is leap year|2001|_show_result=y}}: 2001 AD is not a leap year.<br />
* {{tld|is leap year|2004|_show_result=y}}: 2004 AD is a leap year.<br />
* {{tld|is leap year|2005|_show_result=y}}: 2005 AD is not a leap year.<br />
* {{tld|is leap year|2007|_show_result=y}}: 2007 AD is not a leap year.<br />
* {{tld|is leap year|2008|_show_result=y}}: 2008 AD is a leap year.<br />
* {{tld|is leap year|2009|_show_result=y}}: 2009 AD is not a leap year.<br />
* {{tld|is leap year|2100|_show_result=y}}: 2100 AD is not a leap year in the Gregorian calendar ''(but not in the Julian calendar)''.<br />
* {{tld|is leap year|2400|_show_result=y}}: 2400 AD is ''effectively'' a leap year ''(in both the Julian and Gregorian calendars)''.<br />
* {{tld|is leap year|1900|_show_result=y}}: 1900 AD is not a leap year in the Gregorian calendar ''(but not in the Julian calendar)''.<br />
* {{tld|is leap year|1800|_show_result=y}}: 1800 AD is not a leap year in the Gregorian calendar ''(but not in the Julian calendar)''.<br />
* {{tld|is leap year|1700|_show_result=y}}: 1700 AD is not a leap year in the Gregorian calendar ''(but not in the Julian calendar)''.<br />
* {{tld|is leap year|1600|_show_result=y}}: 1600 AD is ''effectively'' a leap year ''(in both the Julian and Gregorian calendars)''.<br />
* {{tld|is leap year|1500|_show_result=y}}: 1500 AD is not a leap year in the [[proleptic Gregorian calendar]] ''(but is leap in the actual Julian calendar)''.<br />
* {{tld|is leap year|0}}: 1 BC is a leap year in the astronomical calendar ''(mostly pointless for actual calendars of such epoch, but correct in the astronomical calendar where it is year 0)''.<br />
* {{tld|is leap year|-100|_show_result=y}}: 101 BC is not a leap year in the astronomical calendar ''(mostly pointless for actual calendars of such epoch, but correct in the astronomical calendar where it is year -100)''.<br />
<br />
Results for fractions like {{tld|is leap year|2000.9|_show_result=y}} are rounded down (floor).<br />
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