Leap Year Calculator

Check whether any year is a leap year, and list every leap year in a range. The next leap year is 2028, with February 29 falling on a Tuesday.

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Ranges are limited to 200 years so the list stays readable.

Guide updated November 2026.

The three leap year rules

A leap year is a year with 366 days instead of 365, with February 29 added. Three rules decide it:

Rule	Test	Result
1	Year divisible by 4	Leap year
2	Year divisible by 100 (a century year)	Not a leap year
3	Century year also divisible by 400	Leap year after all

Rule 3 is the one people forget. It is why 2000 was a leap year but 1900 was not, and why 2100 will not be. The Gregorian calendar produces 97 leap years in every 400-year cycle.

Worked example: 2024 to 2032

Apply the rules year by year. 2024 is divisible by 4, so it is a leap year. 2025, 2026, and 2027 are not divisible by 4. 2028 is divisible by 4 and is not a century year, so it is a leap year. 2029, 2030, and 2031 are not divisible by 4. 2032 is divisible by 4, so it is a leap year. The leap years from 2024 to 2032 are 2024, 2028, and 2032.

The next leap year is 2028. February 29, 2028 falls on a Tuesday, and the leap year after that is 2032.

The century test: 1900 vs 2000 vs 2100

Year	Divisible by 4	Divisible by 100	Divisible by 400	Leap year?
1900	Yes	Yes	No	No
2000	Yes	Yes	Yes	Yes
2100	Yes	Yes	No	No
2024	Yes	No	No	Yes
2028	Yes	No	No	Yes

Why leap years exist

Earth takes about 365.2422 days (the tropical year) to orbit the sun, roughly a quarter day more than the 365 days on the calendar. Adding February 29 every four years absorbs that extra time and keeps the calendar from drifting away from the seasons. Without leap years, the calendar would drift by about one day every four years, and after a few centuries summer would fall in what the calendar calls winter.

The Gregorian calendar, introduced in 1582, refined the older Julian rule by adding the century exception. That correction is what keeps the calendar accurate to about one day in 3,300 years.

Leap years and your age

Leap days matter for exact date math. A period crossing February 2024 includes a 29th that 2025 and 2026 do not have, so day counts across leap years are one day longer. If you were born on February 29, your birthday is counted on March 1 in non-leap years, the most common legal convention. To find your exact age including leap days, use the Age Calculator, and to measure the gap between any two dates, use the Date Difference Calculator.

For the full story behind the rules, including the history from Julius Caesar to Pope Gregory XIII, see what is a leap year.

Frequently asked questions

Is 2028 a leap year?

Yes. 2028 is divisible by 4 and is not a century year, so February 2028 has 29 days. February 29, 2028 falls on a Tuesday. The next leap year after 2028 is 2032.

What are the three leap year rules?

Rule 1: a year divisible by 4 is a leap year. Rule 2: a century year, divisible by 100, is not a leap year. Rule 3: a century year divisible by 400 is a leap year after all. That is why 2000 was a leap year but 1900 was not, and 2100 will not be.

Was the year 2000 a leap year?

Yes. Although 2000 is a century year, it is divisible by 400, so the third rule applies and February 2000 had 29 days. The century years 1900 and 2100 fail that test and are not leap years.

Why do we have leap years?

Earth takes about 365.2422 days to orbit the sun, roughly a quarter day more than the 365 days on the calendar. Adding February 29 every four years absorbs that extra time and keeps the calendar from drifting away from the seasons. Without leap years, the calendar would drift by about one day every four years.

What birthday do February 29 babies celebrate in non-leap years?

They celebrate on February 28 or March 1, depending on local custom and law. The legal date varies by jurisdiction, so check local rules for official documents. Our Age Calculator counts February 29 birthdays on March 1 in non-leap years.