Leap Year Checker
Verify whether any calendar year is a leap year and explore Gregorian calendar leap year mathematical rules.
A leap year occurs every 4 years and contains 366 days instead of 365 (adding February 29). The Gregorian rule: A year is a leap year if divisible by 4, unless it is divisible by 100, in which case it must also be divisible by 400 (e.g. 2000 was a leap year, 1900 was not).
Accounts for the astronomical 365.2422-day tropical year orbit.
2026 is not a leap year.
This is a common calendar year with 365 days.
Upcoming Leap Years
What is the Leap Year Rule?
A leap year aligns our 365-day calendar with Earth's 365.2422-day solar orbit:
- The year must be evenly divisible by 4.
- If divisible by 100, it is NOT a leap year...
- Unless the year is also divisible by 400 (e.g., 2000 was a leap year; 1900 was not).
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How to Use Leap Year Checker
Enter Any Year
Type any 4-digit or historical year into the checker box.
Instant Verification
See an immediate visual indicator of whether the year has 365 or 366 days.
View Upcoming Leap Years
Browse the next upcoming leap years in the schedule table below.
Practical Examples & Conversions
Year 2024
Leap Year (366 days)
Frequently Asked Questions (PAA)
Related Tools & Converters
Authoritative Standards & Citations
Calculations and algorithms on this page are implemented and verified in strict accordance with the following official technical specifications: