Date & Time calculator
Leap Year Calculator
Check whether a year is a leap year, how many days it has, and the next leap year.
FormulaLeap year = divisible by 4, except years divisible by 100 must also be divisible by 400
Formula
Gregorian leap year rule
Leap year = divisible by 4, except years divisible by 100 must also be divisible by 400
2028 is a leap year. 2100 is not, because it is divisible by 100 but not by 400.
FAQ7 common questions for this calculator.
FAQs
How do I know if a year is a leap year?+
A year is a leap year if it is divisible by 4, unless it is a century year that is not divisible by 400.
How many days are in a leap year?+
A leap year has 366 days.
Is every fourth year a leap year?+
Almost, but century years such as 2100 are excluded unless they are divisible by 400.
How does the Leap Year Calculator calculate the result?+
For the Leap Year Calculator, it uses the Gregorian leap year rule: Leap year = divisible by 4, except years divisible by 100 must also be divisible by 400. 2028 is a leap year. 2100 is not, because it is divisible by 100 but not by 400.
What information do I need to use the Leap Year Calculator?+
For the Leap Year Calculator, enter the relevant dates, times, timezone, or calendar settings requested by the form. Exact dates matter because month lengths, leap years, and boundary days can change the result.
How accurate is the Leap Year Calculator?+
Leap Year Calculator is accurate for the values and assumptions entered on this page. It uses the Gregorian leap year rule. Recheck the inputs before relying on the estimate.
What should I check before using the Leap Year Calculator result?+
For the Leap Year Calculator, check the date and time fields, date format, timezone, daylight-saving changes, inclusive or exclusive endpoints, and whether weekends or holidays should count.
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Date & Time guide
How to use the Leap Year Calculator
Check whether a year is a leap year, how many days it has, and the next leap year. The page also explains the gregorian leap year rule and shows a practical example: 2028 is a leap year. 2100 is not, because it is divisible by 100 but not by 400.
- 1
Enter your details
Enter the values for the leap year calculator scenario you want to check.
- 2
Check the calculation
Review the result alongside the gregorian leap year rule: Leap year = divisible by 4, except years divisible by 100 must also be divisible by 400.
- 3
Compare scenarios
Change one or more inputs to see how they affect the leap Year Calculator result before you use the estimate.