Leap Year Calculator
Enter a year to see whether February has 29 days and which rule decides it.
Check a year
The Gregorian rule
- A year divisible by 4 is a leap year…
- …except a year divisible by 100, which is not…
- …except a year divisible by 400, which is.
So 2024 and 2028 are leap years, 1900 and 2100 are not, and 2000 was.
Why the exceptions exist
A solar year is about 365.2422 days. Adding a day every 4 years gives an average of 365.25 days — slightly too long. Dropping three leap days every 400 years brings the average to 365.2425 days, which drifts by only about one day in 3,200 years.
Leap years this century
2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052, 2056, 2060, 2064, 2068, 2072, 2076, 2080, 2084, 2088, 2092 and 2096. The year 2100 will not be a leap year.