Calculators › Leap year checker
Leap year checker
Enter a year — the leap-year verdict, the rule applied and the next leap year update instantly.
Calculator
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Verdict
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How it works
A year is a leap year if it is divisible by 4 — unless it is divisible by 100, in which case it must also be divisible by 400. So 2024 is a leap year, 1900 was not, and 2000 was. This keeps the average year at 365.2425 days against the solar year's ~365.2422.
Frequently asked questions
Why isn't every fourth year a leap year?
Because the solar year is slightly shorter than 365.25 days. Skipping three century leap years every 400 years removes the surplus and keeps the calendar aligned.
Will 2100 be a leap year?
No — 2100 is divisible by 100 but not by 400, so it is a common year. 2000 was a leap year because it is divisible by 400.
What about birthdays on February 29?
Leap-day birthdays occur only in leap years; the usual convention celebrates them on March 1 in common years.