What this calculator does
Working out whether a year is a leap year comes down to a rule with an exception, and an exception to the exception: divisible by 4 is usually enough, except century years, which are only leap years if they also divide evenly by 400. This calculator applies that rule to any year and states the answer plainly, along with the nearest leap years either side.
The exception is what trips people up: 1900 was not a leap year, despite dividing evenly by 4, because it divides by 100 but not by 400. The year 2000 was a leap year, because it clears all three tests. Rather than working through the rule by hand, entering any date here checks the year it falls in and shows which part of the rule decided the answer.
The formula
A year is a leap year if it divides evenly by 4. If it also divides evenly by 100, it is not a leap year, unless it divides evenly by 400 as well, in which case it is a leap year after all. This calculator applies each part of the rule in order and states which one decided the result.
| Term | Meaning |
|---|---|
| Leap year | A year with an extra day, 29 February, added to keep the calendar aligned with the time the Earth actually takes to orbit the sun. |
| The 4/100/400 rule | Divisible by 4 is a leap year, unless also divisible by 100, unless also divisible by 400. |
| Next / previous leap year | The nearest leap years after and before the year checked. |
The inputs explained
| Field | What to enter |
|---|---|
| A date in the year to check | Any date in the year you want to check. Only the year is used; the month and day do not affect the result. |
When to use it
Is it a leap year this year, or a year you are planning around
Booking something for 29 February, or simply settling whether the current year is a leap year, is answered directly rather than needing the rule worked through by hand.
Checking a century year specifically
Century years are the one place the plain "divisible by 4" rule gives the wrong answer on its own, such as is 2028 a leap year against whether 1900 or 2100 are, which is exactly what the 100/400 exception is for.
Working out interest, payroll or lease calculations that count actual days in a year
Anything that counts real days in a year rather than assuming 365 needs to know whether the year in question is 365 or 366 days long, which this calculator states directly.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Which recent and coming years are leap years
A series of years checked against the 4/100/400 rule, including the two most recent century-year exceptions.
| Year checked | Leap year? | Rule that applies |
|---|---|---|
| 2024 | Yes | Divisible by 4, not by 100 |
| 2025 | No | Not divisible by 4 |
| 2026 | No | Not divisible by 4 |
| 2027 | No | Not divisible by 4 |
| 2028 | Yes | Divisible by 4, not by 100 |
| 2000 | Yes | Divisible by 400 |
| 1900 | No | Divisible by 100 but not by 400 |
Questions
What is a leap year?
A leap year is a calendar year with an extra day, 29 February, added to keep the 365-day calendar year roughly in step with the actual time the Earth takes to orbit the sun, which is closer to 365.25 days.
Is it a leap year this year?
Leave the date on today and the calculator states it directly: yes or no, along with which part of the 4/100/400 rule decided the answer for the current year.
Is 2028 a leap year?
2028 divides evenly by 4 and is not a century year, so yes, 2028 is a leap year, with 29 February added to the calendar that year.
When is the next leap year?
Enter today’s date, or any date, and the next leap year figure shows the nearest one coming up after the year checked, which follows the same 4/100/400 rule as every other leap year.
For the day count of a specific month or year, including the leap day itself, see the days in a year or month calculator. To count the days remaining in the current year, use the weeks left in the year calculator.