Leap Year Calculator
Determine if any year is a leap year using the Gregorian calendar rule.
Results
What is it?
The Leap Year Calculator checks whether any given year is a leap year under the Gregorian calendar system. A leap year has 366 days — February gains an extra day (Feb 29) to keep the calendar aligned with Earth's orbital period of 365.2422 days.
How to use
Enter any year from 1 to 9999 and the calculator instantly tells you if it is a leap year (1 = Yes, 0 = No), how many days are in that year, and approximately how many years remain until the next leap year.
Example scenario
2000 is a leap year (divisible by 400). 1900 is NOT a leap year (divisible by 100 but NOT by 400). 2024 IS a leap year (divisible by 4 and not by 100). 2100 will NOT be a leap year.
Pro tip
The Gregorian rule: a year is a leap year if it is divisible by 4 — EXCEPT for century years (divisible by 100), which must ALSO be divisible by 400. This subtle rule was missing from the Julian calendar (which treated every 4th year as a leap year), causing a drift of about 1 day every 128 years. By 1582, the Julian calendar was 10 days ahead of the solar year, prompting Pope Gregory XIII's calendar reform. If you were born on February 29, your actual birthday only comes around every 4 years — legally you typically celebrate on Feb 28 or Mar 1 in non-leap years.