Leap Year Checker
Check whether any year is a leap year and see the next leap year.
How to Use the Leap Year Checker
A leap year has 366 days instead of 365 because February contains 29 days. This checker applies the Gregorian calendar rule to any year and also finds the next leap year after the value you enter.
Example
2024 is a leap year because it is divisible by 4. 2100 is not a leap year because century years must be divisible by 400, while 2000 qualifies because it is divisible by 400.
Factors That Affect the Result
The checker follows the Gregorian rule: divisible by 4, except years divisible by 100 are excluded unless also divisible by 400. This rule matters for date differences, annual progress calculations and February-based schedules.
Frequently Asked Questions
How often do leap years occur?
Usually every four years, with century exceptions.
Why is 2100 not a leap year?
It is divisible by 100 but not by 400.
Does a leap year affect annual day counts?
Yes. Leap years contain 366 calendar days.
Understanding Leap Year Checker Results
This tool is designed for a specific calendar or time-planning task, so the result depends on the exact dates, times and conventions entered. Review boundaries such as midnight, week starts, month lengths and schedule assumptions when they apply. For planning across time zones, daylight-saving transitions or organization-specific calendars, verify those rules separately rather than treating a simple elapsed-time result as universal.
Calculation Details and Edge Cases
Under the Gregorian calendar, a year is a leap year when divisible by 4, except century years must also be divisible by 400. That makes 2000 a leap year but 1900 not one; historical dates can require different calendar rules.