Leap Year Calculator
Check whether any year is a leap year under Gregorian rules — with its February length, days in the year, and the next and previous leap years.
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What this tool does
Check whether any year is a leap year under Gregorian rules — with its February length, days in the year, and the next and previous leap years. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
How to use the Leap Year Calculator
- Enter or select year (1–9999).
- Read the calculated result; change any measurement to compare alternatives.
Formula
a year is a leap year if it is divisible by 4, except century years, which are leap years only if divisible by 400 (2000 yes, 1900 and 2100 no)
- year
- Year (1–9999)
Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
Worked example
For leap year calculator, the following measurements illustrate the exact method: Year (1–9999): 2028.
Inputs
- Year (1–9999)2028
Result
- Is it a leap year?Yes
- Days in the year366
- Days in February29
- Next leap year2,032
- Previous leap year2,024
Results explained
- Is it a leap year?
- Is it a leap year? from the formula above. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
- Days in the year
- Days in the year from the formula above. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
- Days in February
- Days in February from the formula above. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
- Next leap year
- Next leap year from the formula above. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
- Previous leap year
- Previous leap year from the formula above. Applies the Gregorian leap-year rule proleptically to any year from 1 to 9999. 'Next/previous leap year' are strictly after/before the entered year.
Frequently asked questions
Divisible by 4 means leap year — except century years, which are leap years only when divisible by 400. So 2024 and 2000 are leap years, but 1900 and 2100 are not, even though they divide by 4.
No. 2100 divides by 4 and by 100 but not by 400, so February 2100 has 28 days and the next leap year after 2096 is 2104 — an eight-year gap.
A solar year is about 365.2422 days. Adding February 29 roughly every four years keeps the calendar aligned with the seasons; the century exceptions fine-tune the average Gregorian year to 365.2425 days.
People born on February 29 get a true birthday in leap years only — usually every four years, with the 2096–2104 gap breaking the pattern for those alive then. In other years it is commonly celebrated on February 28 or March 1.
Enter any year and the tool reports the next leap year strictly after it. From the mid-2020s, the sequence runs 2028, 2032, 2036 — every four years until the 2100 exception.