Leap Year Checker
The leap year rule
A year divisible by 4 is a leap year, but a year divisible by 100 is a leap year only if it is also divisible by 400. So 2000 was a leap year, while 1900 and 2100 are not.
Why leap years exist
Earth takes about 365.24 days to orbit the Sun. Adding a day roughly every fourth year keeps the calendar aligned with the seasons.
Frequently asked questions
How is age counted for 29 February births?
Our age calculator treats the birthday as 28 February in non-leap years.
How is a leap year decided?
A year is a leap year if it is divisible by 4, except century years, which must be divisible by 400. So 2000 was a leap year, but 1900 and 2100 are not.
Is this tool free?
Yes. It is free to use, with no sign-up or login.
Does it work on my phone?
Yes. The page works on phone, tablet and computer browsers.
Is 2100 a leap year?
No. It is divisible by 100 but not by 400, so it is not a leap year.
How many days does a leap year have?
366 days. February has 29 days instead of 28.
Can I check any year?
Yes. Type any year and the tool tells you at once whether it is a leap year.