Leap Year Calculator: Is This a Leap Year?
Enter a year from 1 to 9999 to find out if it has a 29 February.
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Formula
A year is a leap year when year mod 4 = 0 and (year mod 100 ≠ 0 or year mod 400 = 0).
A leap year has 366 days; any other year has 365.
Worked example
2024: 2024 ÷ 4 = 506 with no remainder and it is not a century year, so it is a leap year with 366 days. The next one is 2028. For 1900: divisible by 100 but not by 400, so it is a common year.
Frequently asked questions
What is the rule for a leap year?
A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. So 2024 is a leap year with 366 days, and 2023 is not.
Why is 1900 not a leap year but 2000 is?
Both are century years. 1900 is not divisible by 400, so it is a common year with 365 days. 2000 ÷ 400 = 5 exactly, so it is a leap year.
What is the next leap year after 2096?
It is 2104, not 2100. 2100 is a century year that is not divisible by 400, so the usual four-year gap becomes eight years.
Why do we have leap years at all?
A solar year is about 365.2425 days long. Adding one day every four years, minus three skipped days every 400 years, keeps the calendar in step with the seasons.