Check whether a year is a leap year and find the next one.
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How do you check if a year is a leap year?
A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. Leap years add 29 February to keep the calendar aligned with Earth's orbit. For example, 2024 is a leap year, 1900 is not (divisible by 100 but not 400), and 2000 is (divisible by 400).
Understanding your result
Leap years add 29 February to keep the calendar aligned with Earth’s orbit.
Formula and method
A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400.
Assumptions and limitations
The check uses the Gregorian rule of divisibility by 4, 100 and 400, so results for years before that calendar's adoption are theoretical rather than historically accurate. It answers whether a year contains 29 February and does not model other calendars, leap seconds or any regional differences in when the reform took effect.
Worked example
2024 is a leap year; 1900 is not (divisible by 100 but not 400); 2000 is (divisible by 400).
How to use this tool
- Enter a year.
- See whether it is a leap year and why.
Common mistakes to avoid
- Assuming every year divisible by 4 is a leap year — century years are the exception.
About the Leap Year Checker
Check whether a year is a leap year, see the reason, and find the previous and next leap years.
Who should use this tool
Anyone planning dates or curious about the calendar.
Benefits
- Confirms instantly whether any year contains 29 February.
- Explains the reason using the divisible-by-4, 100 and 400 rules.
- Points you to the previous and next leap years for context.
- Handles century-year exceptions such as 1900 and 2000 correctly.
Practical use cases
- Checking whether a given year has 366 days.
- Planning around a 29 February date or birthday.
- Teaching or learning how the leap-year rule works.
- Verifying date logic when building schedules or spreadsheets.
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Frequently asked questions
Why isn’t 1900 a leap year?
It is divisible by 100 but not by 400, so it is not a leap year.
How often is a leap year?
Almost every four years, with century-year exceptions.
Are years like 2100 and 2200 leap years?
No. Century years are only leap years when divisible by 400, so 2000 qualifies but 2100, 2200 and 2300 do not, despite being divisible by 4. The next century year that is a leap year after 2000 is 2400.