Leap Year Calculator

Is a year a leap year? Days in the year, February length and the next leap year.

Leap Year Calculator

Worked example result
Is it a leap year?Yes
Days in the year366
Days in February29
Next leap year2,028

2024 is a leap year: 366 days, 29 days in February, and the next leap year after it is 2028.

Check any year against the Gregorian leap-year rule: leap years have 366 days with a February 29, and they keep the calendar aligned with Earth's orbit.

Along with the yes/no answer you get the number of days in the year, the length of its February, and the next leap year after the one entered.

The formula

Leap if (year ÷ 4 remainder 0 AND year ÷ 100 remainder ≠ 0) OR year ÷ 400 remainder 0

Worked example

2024 is a leap year: 366 days, 29 days in February, and the next leap year after it is 2028.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

Why is 1900 not a leap year but 2000 is?

Century years must be divisible by 400. 1900 is divisible by 100 but not 400, so it was a common year; 2000 is divisible by 400, so it was a leap year.

Why do leap years exist?

A solar year is about 365.2422 days. Adding February 29 roughly every four years — with the century corrections — keeps calendar dates aligned with the seasons.

Category: Date & Time calculators