Leap Year Calculator

Written byOleh Soloninupdated 10 September 2026

Year

Count leap years through to

Result

Verdict2026 is a common year
Days in the year365
Next leap year2,028
Previous leap year2,024
29 Februarythere is no 29 February this year
Leap years in the range6

Three rules, not one

Checks whether a year is a leap year, finds the nearest leap years either side, and counts how many fall in a given range.

'Divisible by four' is only part of the story. The full rule has three parts: a year is a leap year if it divides by 4, is not one if it divides by 100, and is one after all if it divides by 400. Which is why 1900 was a common year and 2000 was not.

Those exceptions exist because the year runs 365.2422 days rather than exactly 365.25. Adding a day every four years would drift by a full day every 128 years, and the century rule removes almost all of that error.

What this calculator shows

Whether the year is a leap year and how many days it holds
The nearest leap years before and after
The weekday of 29 February and the count of leap years in a range

What to keep in mind

The calculation uses the Gregorian calendar, so years before 1583 are not supported — before the reform only the four-year rule applied.
The Gregorian mean year is 365.2425 days, which differs from the astronomical one by 26 seconds.

FAQs

Which years are leap years?

Those divisible by 4, except those divisible by 100 unless they are also divisible by 400. 2024 and 2000 are leap years; 1900 and 2100 are not.

Why was 1900 not a leap year?

It divides by 100 but not by 400, so it falls under the exception. The same will apply to 2100, 2200 and 2300.

Why do we need leap years at all?

The Earth orbits the Sun in 365.2422 days. Without an extra day every four years the calendar would drift by about a day every four years, and over centuries summer would slide into winter.

How many leap years are in a century?

Usually 24 or 25. The 21st century has 25, from 2000 to 2096, because 2100 will not be one.

Worked example

The years nearby

Input: 2026, counting to 2050

Output: A common year of 365 days; the next leap year is 2028

Note: The range 2026 to 2050 holds exactly six leap years: 2028, 2032, 2036, 2040, 2044 and 2048. None of them runs into the century exception.

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Result

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