Leap Year Checker

Instantly check whether any year is a leap year, using the standard Gregorian calendar rule (divisible by 4, except centuries not divisible by 400).

The leap year rule is one of those pieces of calendar trivia that most people know exists but can't quite state correctly from memory: "every four years" is the commonly remembered version, but it's incomplete — century years like 1900 are the exception to that rule, skipped unless they're also divisible by 400, which is why 2000 was a leap year but 1900 and 2100 are not, a detail that trips up plenty of people who confidently know the "every four years" part.

That extra century-based exception exists because a year isn't exactly 365.25 days long — it's closer to 365.2422 days — and the simple every-fourth-year rule alone would overcorrect slightly, drifting the calendar out of sync with the actual seasons over centuries if left uncorrected. The 100/400 exception is a finer correction on top of the coarser four-year one.

This tool just answers the question directly: type in any year, and it tells you immediately whether it's a leap year, applying the full rule correctly rather than the commonly misremembered simplified version — useful for anyone double-checking a specific year, or just settling an argument about whether a particular century year counted.

1. Type in a year.
2. Press Check.
3. See whether it's a leap year, and how many days it has.