How it works
A year is leap if divisible by 4, except century years must also be divisible by 400.
Input definitions
- Gregorian year (1–9999)
- Enter the value in the labeled unit.
A worked example
- Gregorian year (1–9999)
- 2000
Assumptions & limits
Proleptic Gregorian calendar only; historical local calendar adoption is not modeled.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Why was 2000 a leap year but 1900 was not?
Century years are leap years only when divisible by 400. The year 2000 meets that rule; 1900 does not, even though both are divisible by 4.
Do daylight-saving changes affect calendar date results?
Date-only operations compare Gregorian calendar dates at UTC midnight. They do not count local elapsed hours. Timestamp operations require an explicit offset; individual tool assumptions state boundary rules.
How does the Leap year checker and year length tool work?
A year is leap if divisible by 4, except century years must also be divisible by 400.
What are the assumptions and limits of Leap year checker and year length?
Proleptic Gregorian calendar only; historical local calendar adoption is not modeled.