Check whether a year is a leap year and how many days it has.
A year is leap when it is divisible by four, except century years which must also be divisible by four hundred. The leap rule keeps the calendar aligned with the solar year, and it decides whether February has 28 or 29 days.
Leap Year Check
Leap year = divisible by 4 but not by 100, unless also divisible by 400
Leap year = divisible by 4 but not by 100, unless also divisible by 400 A year is leap when it is divisible by four, except century years which must also be divisible by four hundred.
The leap rule keeps the calendar aligned with the solar year, and it decides whether February has 28 or 29 days.
This calculator takes 1 input: Year. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.