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November 01, 2004
Determining whether a year is a Leap Year
This tip explains how to determine whether the year in a date used in a OpenOffice Calc spreadsheet is a leap year.In the Gregorian calendar, a normal year consists of 365 days. Because the actual length of a sidereal year (the time required for the Earth to revolve once about the Sun) is actually 365.25635 days, a "leap year" of 366 days is used once every four years to eliminate the error caused by three normal (but short) years. Any year that is evenly divisible by 4 is a leap year: for example, 1988, 1992, and 1996 are leap years.
However, there is still a small error that must be accounted for. To eliminate this error, the Gregorian calendar stipulates that a year that is evenly divisible by 100 (for example, 1900) is a leap year only if it is also evenly divisible by 400.
For this reason, the following years ARE NOT leap years 1700, 1800, 1900, 2100, 2200, 2300, 2500, 2600 because they are evenly divisible by 100 but NOT by 400.
The following years ARE leap years
1600, 2000, 2400
because they are evenly divisible by both 100 and 400.
The following formula will determine whether the year number entered into a cell (in this example, cell B3) is a leap year:
=IF(OR(MOD(B3;400)=0;AND(MOD(B3;4)=0;MOD(B3;100)<>0));"Leap Year"; "NOT a Leap Year")
Posted by Dave at November 1, 2004 05:05 AM