Leap Year Checker
Find out whether any year is a leap year, and why.
Runs entirely in your browser.
Check If a Year Is a Leap Year
About Leap Year Checker
A year is a leap year if it divides by 4, except that century years must also divide by 400. So 2024 is a leap year, 1900 was not, and 2000 was. The 400-year exception exists because the solar year is about 365.2422 days - slightly less than 365.25, so dropping three leap days every four centuries keeps the calendar aligned.
This matters in code more than it looks. Hard-coding 365 days in a year, or testing only the divide-by-4 rule, produces bugs that surface on 29 February or in century years.
Other Date Tools
- Date Calculator — difference, arithmetic and age on one page
- Age Calculator — exact age and days to the next birthday
- Date Difference — the span between two dates
- Add or Subtract Days — date arithmetic
- Day of the Week — weekday, day of year and ISO week
- Unix Timestamp — epoch seconds to and from a date
- Time Converter — seconds, minutes, hours, days, weeks
