About the Leap Year Calculator
Whether a year is a leap year, with the next ones and the rule explained.
Also known as: is it a leap year, leap year checker, 366 days year, february 29 calculator.
How to use this calculator
- Enter year.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
leap = (year % 4 = 0 and year % 100 ≠ 0) or year % 400 = 0
Worked example
Using the values pre-filled in the calculator above:
- Year = 2,026
the calculator returns:
- Is 2026 a leap year?: No
- Days in the year: 365
- Days in February: 28
- Reason: Not divisible by 4