Leap Year Checker
Check whether any year is a leap year, see why under the Gregorian rule, and find the next and previous ones.
How it works
leap year if divisible by 4 · except century years, which must also be divisible by 400
The Gregorian rule has three steps: a year divisible by 4 is a leap year, unless it is divisible by 100, unless it is also divisible by 400. So 2024 and 2028 are leap years, 1900 and 2100 are not, but 2000 is. This correction keeps the calendar aligned with the solar year of about 365.2425 days — a plain every-four-years rule would drift by roughly three days every 400 years.
Worked example
2024 is divisible by 4 and is not a century year, so it is a leap year with 366 days and a 29-day February. The next leap year is 2028; the previous one was 2020.
Sources: Leap year — Wikipedia
Frequently asked questions
Why are some century years not leap years?
A plain every-four-years rule over-corrects. Skipping the leap day in three out of every four century years (keeping only those divisible by 400) matches the solar year of 365.2425 days far more closely.
Was 2000 a leap year?
Yes. It is a century year but divisible by 400, so it kept its leap day — unlike 1900 and 2100, which are not divisible by 400.
How often does a leap year occur?
Almost every four years — 97 times in every 400 years, because three century years in each 400-year cycle are skipped.
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This calculator is for educational purposes. Double-check important results before acting on them.