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LeapYearQ[date]

returns True if the year corresponding to date is a leap year.

Details and Options
Details and Options Details and Options
Examples  
Basic Examples  
Options  
CalendarType  
Applications  
Possible Issues  
See Also
Related Guides
History
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LeapYearQ

LeapYearQ[date]

returns True if the year corresponding to date is a leap year.

Details and Options

  • The date can be specified in the following forms:
  • DateObject[…]date object
    {y,m,d}year, month, day
    {y,m}the first day of the specified month
    {y}the first day of the first month of the year y
    "string"date as a string ("Jan. 1, 2000")
    numberAbsoluteTime specification
  • The following options can be given:
  • CalendarType "Gregorian"calendar in which the date parameters have been specified

Examples

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Basic Examples  (4)

Find whether a date is in a leap year:

Wolfram Language code: LeapYearQ[DateObject[{1959, 8, 29}, "Day", "Gregorian", -6.]]

Use a compact DateList:

Wolfram Language code: LeapYearQ[{1959}]

An AbsoluteTime specification is allowed:

Wolfram Language code: DateList[3*^9]
Wolfram Language code: LeapYearQ[3*^9]

Use a string specification:

Wolfram Language code: LeapYearQ["2024"]

Options  (3)

CalendarType  (3)

A leap year in the Jewish calendar is defined as a year of 13 months:

Wolfram Language code: LeapYearQ[{#}, CalendarType -> "Jewish"]& /@ Range[5770, 5780]

In the Islamic tabular calendar, leap years are defined as those years that have a 30-day 12th month:

Wolfram Language code: LeapYearQ[{#}, CalendarType -> "Islamic"]& /@ Range[1430, 1460]

In the Julian calendar, every fourth year is a leap year:

Wolfram Language code: LeapYearQ[{#}, CalendarType -> "Julian"]& /@ Range[1890, 1900]

Applications  (1)

Find the periodicity of leap years in different calendars by analyzing a range of 5000 years:

Wolfram Language code: findLeapYearPeriod[calendar_] := Module[{leapQ, repeat}, leapQ = LeapYearQ[{#}, CalendarType -> calendar]& /@ Range[5000]; repeat = FindRepeat[leapQ]; {Count[repeat, True], Length[repeat]} ]

In the Julian calendar, every fourth year is a leap year:

Wolfram Language code: findLeapYearPeriod["Julian"]

There are 97 leap years every 400 years in the Gregorian calendar:

Wolfram Language code: findLeapYearPeriod["Gregorian"]

In the Jewish calendar, there are 7 leap years every 19 years:

Wolfram Language code: findLeapYearPeriod["Jewish"]

There are 11 leap years in each cycle of 30 years of the tabular Islamic calendar:

Wolfram Language code: findLeapYearPeriod["Islamic"]

Possible Issues  (1)

LeapYearQ accepts both DateList and AbsoluteTime specifications, so numeric inputs are treated as a number of seconds since 1900:

Wolfram Language code: LeapYearQ[1996]

For year specifications, either a DateList or DateObject form should be used:

Wolfram Language code: LeapYearQ[{1996}]
Wolfram Language code: LeapYearQ[DateObject[{1996}, "Year", "Gregorian", -6.]]
Wolfram Research (2012), LeapYearQ, Wolfram Language function, https://reference.wolfram.com/language/ref/LeapYearQ.html (updated 2014).

Text

Wolfram Research (2012), LeapYearQ, Wolfram Language function, https://reference.wolfram.com/language/ref/LeapYearQ.html (updated 2014).

CMS

Wolfram Language. 2012. "LeapYearQ." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/LeapYearQ.html.

APA

Wolfram Language. (2012). LeapYearQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/LeapYearQ.html

BibTeX

@misc{reference.wolfram_2026_leapyearq, author="Wolfram Research", title="{LeapYearQ}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/LeapYearQ.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_leapyearq, organization={Wolfram Research}, title={LeapYearQ}, year={2014}, url={https://reference.wolfram.com/language/ref/LeapYearQ.html}, note=[Accessed: 13-June-2026]}