Leap Year Checker
Check if any year is a leap year with a step-by-step explanation.
Enter multiple years, one per line.
This tool checks whether a given year is a leap year (366 days instead of the usual 365) and explains why, based on the actual leap year rules - which are more nuanced than just "divisible by 4."
Frequently asked questions
A year is a leap year if it's divisible by 4, EXCEPT if it's also divisible by 100 - unless it's also divisible by 400, in which case it IS a leap year after all. This is why 2000 was a leap year but 1900 was not, despite both being divisible by 100.
Earth's orbit around the sun takes approximately 365.25 days, not exactly 365 - leap years add an extra day roughly every 4 years to keep our calendar synchronized with the actual solar year over long periods.
Yes - enter any year to check whether it follows (or would follow) the standard leap year rules.