What's the rule for a leap year?

A year is a leap year if it's divisible by 4, except for years divisible by 100 — unless that year is also divisible by 400. So 2024 and 2000 are leap years, but 1900 and 2100 are not, even though both are divisible by 4.

Why does the rule exclude century years like 1900?

Earth's orbit takes about 365.2422 days, not exactly 365.25. Adding a leap day every 4 years overcorrects slightly, so the Gregorian calendar skips the leap day in century years not divisible by 400 to keep the calendar in sync with the seasons over long periods.

How many days does February have in a leap year?

29 days instead of the usual 28 — that extra day is what makes a leap year 366 days instead of 365.

Is my input sent anywhere?

No. The leap year check is a simple divisibility calculation done entirely in your browser — nothing is transmitted or stored.

LEAP YEAR CALCULATOR

Check if a year is a leap year and see the next five. Nothing leaves your browser.

Year

2026Not a leap year2026 is not divisible by 4, so it's not a leap year.

Next 5 leap years from 2026

20282032203620402044

How to check a leap year

1
Enter a year.
2
See instantly whether it's a leap year and why, based on the divisibility rule.
3
Check the next five leap years that follow it.

Questions

What's the rule for a leap year?: A year is a leap year if it's divisible by 4, except for years divisible by 100 — unless that year is also divisible by 400. So 2024 and 2000 are leap years, but 1900 and 2100 are not, even though both are divisible by 4.
Why does the rule exclude century years like 1900?: Earth's orbit takes about 365.2422 days, not exactly 365.25. Adding a leap day every 4 years overcorrects slightly, so the Gregorian calendar skips the leap day in century years not divisible by 400 to keep the calendar in sync with the seasons over long periods.
How many days does February have in a leap year?: 29 days instead of the usual 28 — that extra day is what makes a leap year 366 days instead of 365.
Is my input sent anywhere?: No. The leap year check is a simple divisibility calculation done entirely in your browser — nothing is transmitted or stored.