Date & Time Tools
Leap Year Calculator
Check if any year is a leap year, see the divisibility rule, find the next and previous leap years, and list every leap year in a range.
Current year
No, 2026 is not a leap year
2026 is not divisible by 4, so it is a common (365-day) year.
Days in year
365
28 days in February
Next leap year
2028
Previous leap year
2024
Check any year
Result
No, 2026 is not a leap year
2026 is not divisible by 4, so it is a common (365-day) year.
- Divisible by 4: no
- Divisible by 100: no (century exception does not apply)
- Divisible by 400: no
Days in year
365
February has 28 days
Feb 29 weekday
n/a
no February 29 this year
Next leap year
2028
in 2 years
Previous leap year
2024
2 years ago
Count and list leap years in a range
Enter any two years (inclusive) to count the leap years between them and see the full list.
Result
10 leap years
in the 37-year range from 2000 to 2036 (inclusive)
Common years: 27. Leap years happen roughly every 4 years, with three century skips removed every 400-year cycle.
All leap years in the range
The Gregorian leap year rule
A year is a leap year if it is divisible by 4, except if it is divisible by 100, unless it is also divisible by 400. The century exception keeps the calendar locked to the solar year over a 400-year cycle of 146,097 days (an average of 365.2425 days per year, very close to the actual tropical year of 365.2422 days).
2024
Leap year
Divisible by 4, not by 100. Leap year.
2025
Common year
Not divisible by 4. Common year.
1900
Common year
Divisible by 100, not by 400. Century exception applies.
2000
Leap year
Divisible by 400. Override of the century exception.
2100
Common year
Will be divisible by 100, not by 400. Common year.
2400
Leap year
Will be divisible by 400. Leap year.
- Why every 4 years? One solar year is about 365.2422 days, roughly a quarter of a day longer than 365. Adding a 366th day every four years keeps the seasons aligned with the calendar.
- Why the century skip? Four times 0.2422 is 0.9688, not exactly 1, so leaping every 4 years overcorrects by 0.0312 days per cycle. Skipping the leap on century years that are not divisible by 400 removes 3 of every 100 leap days and brings the long-run average to 365.2425 days per year.
- Before 1582, the Julian calendar treated every fourth year as a leap year without the century exception. This calculator extends the Gregorian rule back to year 1, which is what most modern software, ISO 8601, and astronomical software use (the “proleptic Gregorian” calendar).
- Privacy: every calculation runs in your browser. The years you check are not uploaded anywhere.
How to use
- Read the Current year card at the top to see immediately whether this year is a leap year, why, and the next and previous leap years.
- In the Check any year panel, type a year between 1 and 9999 (or use the This year, plus or minus 1, and plus or minus 4 buttons) to see the result, the rule branch that applies, and the divisibility checks for 4, 100, and 400.
- If the chosen year is a leap year, the result card also shows the weekday for February 29 in that year, useful for birthdays and anniversaries.
- In the Count and list panel, enter any two years to see the total number of leap years in the range, the number of common years, and a list of every leap year that falls inside.
- Use Copy summary or Copy list to paste the result into a spreadsheet, homework page, calendar app, or note.
- Open the Gregorian leap year rule reference at the bottom for worked examples (2024, 1900, 2000, 2100, 2400) and a plain-English explanation of why the calendar uses the 4 / 100 / 400 divisibility rule.
About this tool
Leap Year Calculator answers the everyday questions around leap years on the Gregorian calendar. The headline panel shows whether the current year is a leap year and explains why in a single sentence. The Check any year panel takes any year between 1 and 9999 and reports a clear yes or no plus the exact rule branch that decided the answer (divisible by 4, divisible by 100, divisible by 400), how many days February has that year, what weekday February 29 falls on if it exists, and the next and previous leap years with the gaps in years. The Range panel counts and lists every leap year between any two years (inclusive) using a closed-form formula, so the count is correct even for ranges spanning thousands of years, with quick presets for the current decade, current century, the 1900 to 2100 window that students often need, and the 21st century. The Reference panel works through the canonical examples (2024, 2025, 1900, 2000, 2100, 2400) so the divisibility rule is visible as worked answers, then explains why the 4-year cycle exists, why centuries skip the leap unless they are divisible by 400, and how this calculator extends the rule back to year 1 using the proleptic Gregorian calendar (the same convention ISO 8601 and modern software use). Every calculation runs locally in your browser, so the years you check stay on your device with no signup, no upload, and no analytics. Useful for verifying birthdays and anniversaries that fall on February 29, planning calendars and schedules, fact-checking history dates, school and homework problems on the divisibility rule, and any code that needs to confirm whether a specific year has 365 or 366 days.
Free to use. Works in your browser. No signup, no login.
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