Leap Year Checker
Identify whether a given year includes February 29 by applying the Gregorian leap-year rules used worldwide today.
For calendar reference only.
Examples
- 2024 ⇒ Yes, 2024 is a leap year.
- 1900 ⇒ No, 1900 is not a leap year.
- 2000 ⇒ Yes, 2000 is a leap year.
FAQ
Why isn't 1900 a leap year?
Century years must be divisible by 400. 1900 fails that test, while 2000 passes it.
Does this calculator handle BCE years?
Yes. Use astronomical year numbering, where 1 BCE is year 0, 2 BCE is −1, and so on.
How often do leap years occur?
Roughly every four years, but century years break the pattern unless they satisfy the 400-year rule.
What calendars use different rules?
The Julian calendar treated every fourth year as a leap year. Modern Gregorian calendars fine-tuned the rule to stay aligned with the seasons.
Additional Information
- Leap years add February 29 to keep calendars aligned with Earth's 365.2422-day solar orbit.
- Century years must be divisible by 400 to remain leap years (e.g., 2000 yes, 2100 no).
- Astronomers extend the Gregorian rules backward and forward in time using the proleptic Gregorian calendar.