Leap Year Checker
Is it a leap year? Enter any year to find out — plus see the previous, next, and upcoming leap years.
Enter a year and click Check to see if it is a leap year, along with the previous and next leap years.
Disclaimer: The results provided by this tool are estimates for informational purposes only. Actual values may vary. Please verify important calculations independently.
How leap years are determined
The Gregorian leap year rule is a three-step test. A year is a leap year if it is evenly divisible by 4, unless it is also evenly divisible by 100, in which case it must additionally be divisible by 400 to qualify. The year 2024 is divisible by 4 and is not a century year, so it is a leap year. The year 2000 is divisible by 100 but also by 400, so it leaps. The year 1900 is divisible by 100 but not by 400, so it does not leap. This layered rule produces exactly 97 leap years in every 400-year cycle rather than the 100 a naive 'every fourth year' rule would give.
The 400-year cycle contains 146,097 days, which is exactly 20,871 weeks. That makes the Gregorian calendar repeat itself precisely every 400 years — a property used by some perpetual calendar algorithms to simplify date computations. The average calendar year under this rule is 365.2425 days, which tracks the mean tropical year of roughly 365.2422 days to within one day per 3,300 years. That accuracy is why the Gregorian calendar has remained the civil standard for 443 years and counting without needing another reform.
Practical leap year considerations
Leap years matter most at year boundaries and for date arithmetic that crosses February. Payroll systems sometimes need to accommodate an extra working day in leap years, especially for salaried employees whose annual compensation is divided by working days rather than a fixed 260. Billing systems that prorate daily across a year produce slightly different per-day rates in leap years. Software that hardcodes a 365-day year for time series or depreciation schedules can drift by up to a day over a leap cycle — a subtle bug that only surfaces on February 29 or in multi-year totals.
People born on February 29 — known as leaplings or leap-day babies — face their own calendar quirks. Many jurisdictions treat March 1 as the legal birthday in common years for purposes like driving privileges or alcohol purchase age, while others treat February 28. Celebrations tend to follow personal preference, with some leaplings observing every four years on the true date and others marking February 28 or March 1 annually. Upcoming leap years include 2028, 2032, 2036, and 2040; 2100 will be skipped because it is a century year not divisible by 400.