Category: Date & time
Leap Year Checker
Check whether a year is a leap year, and find the next one
Check whether any year is a leap year under the Gregorian calendar rule, see how many days its February has, and find the next leap year after it. Runs entirely in your browser.
Everything on this page is processed in your browser. Nothing is uploaded.
What this tool does
The Gregorian calendar adds a leap day to keep the calendar aligned with Earth's orbit: a year is a leap year if it divides evenly by 4, except that century years must divide evenly by 400 rather than just 100. That's why 2000 was a leap year but 1900 and 2100 are not. This tool applies that rule to any year you enter, showing whether it has 29 or 28 days in February and how many years until the next leap year.
How to use it
- Type a year, e.g. 2024.
- See whether it's a leap year and how many days its February has.
- Check the next leap year after it.
Privacy
This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.
Frequently asked questions
- Why isn't 1900 a leap year if it's divisible by 4?
- Century years are the exception: they're only leap years when divisible by 400. 1900 divides by 4 and by 100 but not by 400, so it wasn't a leap year; 2000 divides by 400, so it was.
- Does this work for years before 1582?
- The calculation applies the same arithmetic rule regardless of year, though the Gregorian calendar itself wasn't adopted everywhere until 1582 or later, so very old dates may have used a different calendar in practice.
- Is my input sent anywhere?
- No. The year is calculated locally in your browser.