Leap Year Checker
Check whether a year has 365 or 366 days using the Gregorian leap-year rule. Free, private and instant.
Processed locally in your browserPrivate by design. Dates stay in this browser and are not saved.
Enter a year to check February.
The leap-year rule
In the proleptic Gregorian calendar, years divisible by 4 are leap years, except century years must also be divisible by 400. 2000 is leap; 1900 is not. Historical local calendar adoption is not modeled.
How to use Leap Year Checker
- Enter the requested dates or year.
- Adjust optional settings and read the local result.
Useful things to know
Years 1–9999, proleptic Gregorian calendar. Historical local calendar adoption is not modeled.
Is Leap Year Checker free, and how is my privacy handled?
Yes. Leap Year Checker is free to use without registration. Tool inputs are processed in your browser rather than uploaded to our servers. Optional usage analytics follows your cookie preferences; it does not receive your files or tool inputs. Keep your browser updated and review results before sharing.