Leap Year Detector
Check if any year is a leap year. See days in February, divisibility rules, and the next and previous leap years. Free, runs 100% in your browser.
Divisibility rule
Previous 5 leap years
Next 5 leap years
Reference
What is a leap year?
A leap year is a year with 366 days instead of the usual 365. The extra day, February 29, compensates for the fact that the Earth takes approximately 365.2422 days to orbit the Sun. Without leap years, our calendar would drift about 24 days every 100 years relative to the seasons.
The leap year rule
A year is a leap year if: (1) it is divisible by 4, AND (2) it is NOT divisible by 100 — UNLESS (3) it is also divisible by 400. For example: 2024 is a leap year (divisible by 4, not by 100). 1900 is NOT a leap year (divisible by 100 but not by 400). 2000 IS a leap year (divisible by 400). This rule, part of the Gregorian calendar introduced in 1582, keeps the calendar accurate to within one day every 3,236 years.
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