Leap Year Calculator
Applies the Gregorian leap year rule to any year.
Result
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Why —
Days in the year — days
Days in February — days
Previous leap year —
Next leap year —
Reading this —
The formula
leap if divisible by 4 except century years, unless divisible by 400
This is the Gregorian rule, which gives 97 leap years every 400 years.
What to watch out for
A leap year adds 29 February, making 366 days.
Frequently Asked Questions
Was 2000 a leap year?
Yes. It is a century year, but divisible by 400. 1900 was not, because it is not divisible by 400.
How often do leap years happen?
Every 4 years, except that the gap is 8 years around a century year not divisible by 400, such as 2100.
When is a 29 February birthday in other years?
People mark it on 28 February or 1 March. The age and birthday countdown calculators use 28 February. Some places use 1 March in law.