Why was 2000 a leap year but 1900 was not?
Century years must be divisible by 400 to be leap years. 2000 is divisible by 400, but 1900 and 2100 are not.
How to Use Leap Year Checker
Step 1: Enter Year
Type any year (e.g. 2024, 2028, 2100).
Step 2: View Result
See if it contains 366 days and inspect the rule breakdown.
Key Features & Capabilities
- Applies full Gregorian 400-year cycle rules (divisible by 4, except centuries unless divisible by 400)
- Lists the next 10 upcoming leap years
- Historical explanation of the solar calendar drift
Frequently Asked Questions
Why do we have leap years?
Earth takes approximately 365.2422 days to orbit the sun. Adding an extra day every ~4 years prevents calendar seasons from drifting over centuries.
Related Tools
- Day of the Year Calculator — Find the ordinal day number (1–366) and remaining days in the calendar year.
- Week Number Calculator — Find the ISO 8601 week number, start date, and end date for any calendar date.