Work out leap year checker instantly with clear inputs, formula shown and shareable results.
A Gregorian year is a leap year if divisible by four, except centuries, unless divisible by 400. So 2000 was a leap year but 1900 and 2100 are not. 2026 is not - the next is 2028. The rule gives an average year of 365.2425 days against the true tropical year of 365.24219, an error of one day in about 3200 years.
Gregorian rule
leap if divisible by 4, and not by 100 unless also by 400
Average year length
365.2425 days
Because the century exception applies: divisible by 100 but not by 400, so it was skipped to keep the calendar aligned with the seasons.
No. It is divisible by 100 but not 400, so February will have 28 days - the first skipped leap year since 1900.