Leap Year Calculator
Check whether a year is a Gregorian leap year, see February's length, and find the next leap year.
What this calculator does
The Leap Year Calculator estimates your result instantly from the values you enter, using standard date & time formulas. Check whether a year is a Gregorian leap year, see February's length, and find the next leap year. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.
Result
About Leap Year Calculator
The Leap Year Calculator checks a year using the Gregorian divisibility rule. It reports whether the entered year is a leap year, whether February has 28 or 29 days, and the next leap year strictly after the entered year.
Years divisible by 4 are leap years except century years, which must also be divisible by 400. The calculator accepts years of 1 or greater.
Formula & Mathematical Calculation
Leap year = divisible by 4 AND (not divisible by 100 OR divisible by 400)
A leap year has 29 days in February; otherwise February has 28. The next result is found by checking successive years beginning with the entered year plus one.
Calculation Example
Example: 1900 is divisible by 100 but not by 400, so it is not a leap year and February has 28 days. The next leap year after 1900 is 1904.
Key Benefits
- Applies the Gregorian century exception
- Reports February’s day count
- Finds the next strictly later leap year
- Explains which divisibility rule determined the result
How to Use this Calculator
-
Enter a year
Provide a whole-number year of 1 or greater. -
Calculate
Submit the year to apply the divisibility-by-4, 100, and 400 rules. -
Review the result
Read the yes-or-no result, February length, and next leap year.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
- Results use standard published formulas and account only for the values entered above.
- Rounding is applied for display; the underlying calculation uses your full precision.
- Results are returned in the same units you enter, unless the tool states the output unit.
What it does not cover
- Leap Year Calculator produces a calculated result for reference and learning, not a certified or official measurement.
- Real-world outcomes differ when tolerances, rounding rules or local standards apply.
- Definitions and standards vary by region and change over time; verify the convention that applies to your case.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For work where the result carries real consequences, confirm it against an authoritative source.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.