Rules for Determining a Leap Year
- Most years that can be divided evenly by 4 are leap years.
(For example, 2012 divided by 4 = 503: Leap year!)
- Exception: Century years are NOT leap years UNLESS they can be evenly divided by 400. (For example, 1700, 1800, and 1900 were not leap years, but 1600 and 2000, which are divisible by 400, were.)
Read more: http://www.infoplease.com/spot/leapyear2.html