Everyone knows “divisible by 4” — almost nobody remembers the exception that trips up the years people actually ask about. Our new Leap Year Checker walks through the real rule for any year you type, not just the easy 90% case.
- The full rule, not the shortcut — a year is a leap year if it’s
divisible by 4, except century years (ending in
00), which are leap years only if they’re also divisible by 400. That’s why 2000 was a leap year but 1900 and 2100 are not. - Step-by-step reasoning — the page doesn’t just say yes or no, it shows which divisibility checks fired for your specific year, so you can see exactly where the century exception did or didn’t apply.
- Next leap years, automatically — see the next six leap years after whatever year you enter, useful for planning ahead around February 29 birthdays or leap-day events.
- Private by default — the whole calculation is a few modulo operations that run instantly in your browser; nothing is sent to a server.
Type in 1900, 2000, or 2100 to see the century exception in action, or your own birth year to check whether it was a leap year — and if you were born on February 29, when your next real birthday actually falls.