Leap Year Calculator
Check whether a year is a leap year using Gregorian rules and see upcoming leap years.
Result
Complete the fields to see the result.
The calculation runs locally in your browser.
Gregorian leap-year rule
A year is leap when divisible by 4, except century years unless also divisible by 400. Therefore 2000 was leap while 1900 was not.
Days and upcoming years
Leap years have 366 days and include February 29. The tool also lists the next four leap years.
Frequently asked questions
Is every fourth year a leap year?
Usually, but century years must also be divisible by 400.
How many days are in a leap year?
A leap year has 366 days.
Why does February 29 exist?
It compensates for the difference between a 365-day calendar and the approximate solar year.