Leap Year Checker

Check if a year is a leap year and find the next and previous leap years. Free online leap year calculator with explanation.

Enter Year

How It Works

A leap year is a calendar year that contains an additional day (February 29), making it 366 days instead of 365. Leap years are necessary because the Earth takes approximately 365.2425 days to orbit the Sun, not exactly 365. Without leap years, our calendar would gradually drift from the solar year.

Formula

Is Leap Year = (Year % 4 === 0) AND (Year % 100 !== 0 OR Year % 400 === 0)

A year is a leap year if: (1) it is divisible by 4, AND (2) if it is a century year (divisible by 100), it must also be divisible by 400. This means 2000 was a leap year (divisible by 400), but 1900 was not (divisible by 100 but not 400).

Examples

Input	Output
2024	IS a leap year \| Next: 2028 \| Previous: 2020
1900	NOT a leap year \| Next: 1904 \| Previous: 1896
2000	IS a leap year \| Next: 2004 \| Previous: 1996

Frequently Asked Questions

Why do we have leap years?▾

The Earth takes approximately 365.2425 days to orbit the Sun. Without leap years, our calendar would drift by about 1 day every 4 years. Over centuries, this would cause seasons to shift dramatically in the calendar.

Why isn't every century year a leap year?▾

Adding a leap day every 4 years overcorrects slightly (365.25 vs actual 365.2425). The exception for century years (skipping those not divisible by 400) provides a more accurate correction, keeping the calendar aligned over long periods.

What happens if you're born on February 29?▾

People born on February 29 (called "leaplings" or "leapers") typically celebrate their birthday on February 28 or March 1 in non-leap years. Legally, the birthday is recognized on March 1 in many jurisdictions for non-leap years.