Leap Year Calculator
Check whether any year between 1 and 9999 is a leap year, with days in the year and the nearest leap years around it.
Between 1 and 9999.
Is 2026 a leap year?
No
February has 28 days
Days in the year
365
Next leap year
2,028
29 Feb in February
Previous leap year
2,024
Leap days this century
24
29 February falls this many times
Rule
Not divisible by 4
A year is a leap year if it is divisible by 4, except century years which must be divisible by 400 — so 2000 was a leap year but 1900 and 2100 are not.
Leap Year Calculator on True Calculator gives you an instant, accurate answer with no sign-up and no app install. Check whether any year between 1 and 9999 is a leap year, with days in the year and the nearest leap years around it. Every result shows the formula and a worked example so you can verify the calculation yourself, and all values are computed in your own browser — your numbers never leave your device.
Popular uses: leap year checker · is it a leap year · leap year list
Reviewed by the True Calculator team · Last updated: August 2026
How We Calculate
This calculator uses the standard Gregorian calendar with exact month lengths and leap-year rules. All calculations are performed instantly in your browser using JavaScript — no data is sent to any server.
Day and month counts follow the civil calendar used in official records. Leap years are handled automatically, and business-day counts follow the Monday-to-Friday convention.
When to Use This Calculator
Use the leap year calculator whenever you need a quick, authoritative check on whether a year has 366 days — planning February events, verifying dates for contracts or school calendars, checking birthday validity for 29 February, or settling calendar trivia. The output answers the yes-or-no question instantly and adds useful context: the number of days in the year, the nearest leap years around any year, and how many leap days fall in the current century. Students use it for calendar maths and computer-science assignments, event planners use it to confirm whether a February date exists, and developers use it to verify leap logic against a trusted source. The century rule is handled automatically, so there is no need to remember the 400-year exception — the calculator applies it for you.
How to Use This Calculator
- Step 1: Enter a year between 1 and 9999, such as 2026, in the year field.
- Step 2: Read the is-it-a-leap-year card for a clear Yes or No with the February day count.
- Step 3: Check the days-in-the-year card for 365 or 366, and the next and previous leap-year cards for neighbours.
- Step 4: Read the leap-days-this-century card to see how many 29 Februaries occur in the current century.
Worked Example
Entering 2024 returns Yes — it is a leap year with 366 days, and February had 29 days. The previous leap year was 2020 and the next is 2028. Entering 2025 returns No, with 365 days, previous leap 2024 and next leap 2028. The century card shows the 21st century holds 24 leap days, since 2100 is not a leap year. The rule card explains the century exception: 2000 was a leap year, but 1900 and 2100 are not.
Tips and Common Mistakes
- •Tip 1: Test century years specifically — 2000 is a leap year but 1900 and 2100 are not, which surprises most people.
- •Tip 2: Use the next-leap-year card to find when the next 29 February occurs for planning leap-day events.
- •Tip 3: The leap-days-in-century figure is handy for calendar trivia and for building perpetual calendar logic.
- ✗Mistake 1: Assuming every fourth year is a leap year — century years must also be divisible by 400.
- ✗Mistake 2: Entering a year below 1 or above 9999, which the calculator rejects as out of range.
Frequently Asked Questions
What makes a year a leap year?
A year is a leap year if it is divisible by 4, except century years, which must also be divisible by 400. So 2024 was a leap year with 366 days, 2000 was a leap year, but 1900 and 2100 are not. The extra day, 29 February, keeps the calendar aligned with the Earth's orbit.
Why is 2000 a leap year but 1900 is not?
Both are century years, but the leap rule requires century years to be divisible by 400. Since 2000 ÷ 400 = 5 exactly, 2000 was a leap year. Since 1900 ÷ 400 is not whole, 1900 was a common year with 365 days. This exception is the reason 1700, 1800 and 1900 were skipped.
When is the next leap year?
The next leap year after 2026 is 2028, and the calculator lists the nearest leap years around any year you enter. For 2025 the nearest leap years are 2024 (previous) and 2028 (next). The next century leap year is 2400, since 2100, 2200 and 2300 are all common years.
How many leap days fall in a century?
A century has either 24 or 25 leap days. The calculator counts the actual leap years from the first year of the century onwards — for the 21st century that includes 2004, 2008 and so on through 2096, giving 24 leap days, since 2100 itself is not a leap year.
What happens to leap-day birthdays?
People born on 29 February celebrate in non-leap years on 1 March (or 28 February by some conventions). This calculator shows that a leap-day birth still completes one year on every 29 February that exists, and the birthday-calculator on this site shifts the celebration date automatically.
You might also need
Related calculators from other categories
Construction
BTU Calculator
Calculate the BTU and AC tonnage required for a room based on size, sun exposure and insulation.
Construction
Concrete Calculator
Calculate concrete volume, weight and number of cement bags for a slab. Get exact quantities for your construction project.
Construction
Gravel Calculator
Estimate gravel volume, weight in tonnes and 50 kg bags for driveways and paths by material density.
Construction
Mulch Calculator
Work out mulch volume in m³ and litres, plus bags needed and cost for your garden beds.