Leap Year Checker
Check whether any year is a leap year and see upcoming leap years.
A leap year has 366 days, adding February 29 to keep the calendar aligned with Earth's orbit. The rule is trickier than "every four years": a year is a leap year if it's divisible by 4, except century years, which must also be divisible by 400. That's why 2000 was a leap year but 1900 and 2100 are not — a subtlety that has broken plenty of date-handling code.
Enter any year and this checker tells you instantly whether it's a leap year, explains which rule applied, and lists the next several leap years so you can plan around them.
How to use Leap Year Checker
- 1
Enter a year
Any year, past or future.
- 2
See the verdict
Leap year or not, with the applicable rule explained.
- 3
Browse upcoming leap years
The next several are listed automatically.
Features
- Full Gregorian rule (÷4, except ÷100 unless ÷400)
- Explains why each result holds
- Lists upcoming leap years
Frequently asked questions
Common mistakes to avoid
- Treating all century years as leap years — only those divisible by 400 qualify.
- Hardcoding February as 28 days in date calculations.
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