Leap year checker
Type in a year and instantly find out whether it's a leap year, with the rule applied step by step and a list of the next years with a February 29.
The next 10 leap years
Starting from today (updates when you check a year):
The leap year rule: 4, 100 and 400
A year is a leap year if it's divisible by 4 — except years divisible by 100, which are leap years only if they're also divisible by 400. So 2000 was a leap year (2000 ÷ 400 = 5), while 1900 wasn't and 2100 won't be. The correction exists because the solar year lasts about 365 days and 6 hours minus 11 minutes: the plain "+1 day every 4 years" of the old Julian calendar drifted by roughly 3 days every 400 years, an error the 100 and 400 exceptions almost completely cancel out.
Why leap years exist and what happens on February 29
Without leap days, the calendar would slowly slide against the seasons — after a few centuries, July 4th would land in spring. The extra day is February 29, and people born on it are affectionately called "leaplings" or "leap day babies." In common years they celebrate on February 28 or March 1, and for legal purposes (like turning 21) most US states treat March 1 as the birthday in non-leap years. Roughly 1 in 1,461 people is born on a leap day — rare enough that it makes a great icebreaker.