Leap Year Checker
Check whether a year follows the Gregorian leap-year rule.
2026 is not a leap year
In the Gregorian calendar, leap years are divisible by 4, except century years that are not divisible by 400.
Tool guide
About Leap Year Checker
Check whether a year is a leap year under the Gregorian calendar rule. The result helps with ordinary modern dates, but calendars in historical use may follow different conventions.
How to use this tool
- 1Enter a whole-number year in the input.
- 2Run the check and read whether it is marked as a leap year.
- 3Use the relevant local calendar rule if you are checking a historical date.
How the tool works
In the Gregorian calendar, a year is a leap year when divisible by 4, except century years must also be divisible by 400. This keeps the calendar year closer to the solar year than a simple four-year rule.
Worked real-world example
The year 2000 is a leap year because it is divisible by 400; 1900 is not because it is a century year not divisible by 400.
Common scenarios and use cases
Validate a year for date calculations, scheduling, or a calendar exercise.
Important details and limitations
The rule applies to the Gregorian calendar. Some countries adopted it later than others, so historical date records may use a Julian or local calendar.
Check the output unit as well as the number. If the result will be reused in another calculation, retain full precision where possible and round only at the end. For measurements governed by a technical specification, use the standard and tolerance required by that document.
Frequently asked questions
Is every year divisible by four a leap year?
No. Century years are excluded unless divisible by 400.
Why was 2000 a leap year but 1900 was not?
The 400-year exception applies to 2000 only.
Does it convert historical calendars?
No. It checks the Gregorian leap-year rule.