Leap Year Calculator
Check whether any year is a leap year, and see the nearest leap years before and after it.
Nearby leap years
The Leap Year Rule
A year is a leap year if:
- It’s evenly divisible by 4, and
- If it’s also evenly divisible by 100, it must be evenly divisible by 400.
This is why 2000 was a leap year (divisible by 400), but 1900 and 2100 are not (divisible by 100 but not 400).
Why Leap Years Matter for Age Calculations
Anyone born on February 29 only has a “true” birthday once every four years. All of our calculators — including the Chronological Age Calculator — correctly account for leap years automatically, so ages and date differences are always calendar-accurate.
Frequently Asked Questions
What is a leap year?
A leap year has 366 days instead of 365, with an extra day added as February 29. Leap years keep our calendar synchronized with Earth's orbit around the sun.
How do you know if a year is a leap year?
A year is a leap year if it's divisible by 4, except for century years (divisible by 100), which must also be divisible by 400 to be a leap year. For example, 2000 was a leap year, but 1900 was not.
Why do leap years exist?
Earth takes approximately 365.2425 days to orbit the sun — not exactly 365. Without leap years, our calendar would gradually drift out of sync with the seasons.
Related Calculators
Chronological Age Calculator
Calculate exact chronological age in years, months, and days — instantly, with clinical years;months…
Open calculator →Birthday Calculator
See exactly how many days are left until the next birthday, and what age…
Open calculator →Date Difference Calculator
Calculate the exact number of years, months, weeks, and days between any two dates.
Open calculator →Last updated July 17, 2026. Reviewed by the ChronoAge editorial team Our editorial policy
This tool is for informational and professional-reference purposes. Always verify against official records for legal or clinical documentation.