Leap Year Checker
Check whether a year has 366 days — and see the rule behind it.
—Leap year?
—Days in the year
—Previous leap year
—Next leap year
Leap years in a range
● Everything is calculated in your browser. Nothing is sent anywhere.
How it works
In the Gregorian calendar, a year is a leap year if it's divisible by 4, except century years, which must also be divisible by 400. So 2024 is a leap year, 1900 isn't, and 2000 is. This keeps the calendar aligned with the solar year (365.2425 days on average).