How Leap Year Checker Works
A year is a leap year if it's divisible by 4, unless it's also divisible by 100 — in which case it's only a leap year if it's divisible by 400 as well. That extra rule exists because a year is actually about 365.2425 days long, not exactly 365.25, so the calendar skips three leap days every 400 years to stay in sync with the seasons.
How to Use This Tool
- Enter any year, past or future, into the field.
- Select Check Year to see whether it's a leap year and read the reason why.
- Scroll the result to see the next five leap years counting up from the year you entered.
Example
2024 is divisible by 4 and not by 100, so it's a leap year. 1900 is divisible by 100 but not by 400, so it is not a leap year. 2000 is divisible by 400, so it is a leap year after all.
Helpful Tips
- Century years (ending in 00) are the exception to watch for — most of them are not leap years, only the ones divisible by 400 are.
- The next-five-leap-years list is handy for planning anything tied to 29 February, like a leap-day birthday.
- Negative years are accepted too, if you're working with historical or astronomical year numbering.
Frequently Asked Questions
What is the leap year rule?
A year is a leap year if it's divisible by 4, except century years, which must be divisible by 400. That's why 2000 was a leap year but 1900 and 2100 are not.
Why do we have leap years at all?
Earth takes about 365.2425 days to orbit the sun, not exactly 365. Adding a leap day roughly every four years keeps the calendar aligned with the seasons.
How many days does February have in a leap year?
29 days, instead of the usual 28 — that extra day is what makes it a leap year.
Is the year 2000 a leap year?
Yes. Even though it's a century year, it's divisible by 400, so the exception to the exception makes it a leap year.
This tool runs entirely in your browser. Your input is not uploaded to any server.