Leap Year Checker

About this calculator

This tool checks whether a given year is a leap year — a year with 366 days instead of 365 because of an extra day (February 29) added to keep the calendar aligned with Earth's orbit around the sun, which actually takes about 365.2422 days. It follows the full Gregorian rule: divisible by 4, except century years, unless also divisible by 400 (which is why 2000 was a leap year but 1900 was not).

It is used by developers testing date logic in software, event and project planners who need to know whether February has 29 days when scheduling something years out, and by anyone curious about their own birthday quirks — like people born on February 29th, who technically only have a birthday every four years — or wanting to know when the next leap year falls.