Leap Year Calculator
Check if a year is a leap year, with the next and previous ones.
A year is a leap year if it's divisible by 4 — except century years, which must also be divisible by 400. So 2000 was a leap year but 1900 wasn't. Runs in your browser.
Check whether a year is a leap year and see the previous and next leap years plus how many days that year has (365 or 366). A year is a leap year if it's divisible by 4, except century years which must also be divisible by 400 — so 2000 was a leap year but 1900 wasn't. Runs in your browser.
How to use the Leap Year Calculator
- Enter a year.
- See whether it's a leap year and how many days it has.
- Check the previous and next leap years.
Frequently asked questions
What makes a year a leap year?
It must be divisible by 4. Century years (divisible by 100) are an exception: they're only leap years if also divisible by 400. So 2000 was a leap year, but 1700, 1800 and 1900 were not.
Why do we have leap years?
Earth's orbit takes about 365.24 days, so adding February 29 every four years (with the century rule) keeps the calendar aligned with the seasons.