Leap Year Calculator
Check if any year is a leap year, find the next and previous leap years, and list all leap years in a custom range. Uses the Gregorian calendar three-part rule: divisible by 4, excluding century years unless also divisible by 400.
Check a Year
2026 is not a Leap Year
2026 is not divisible by 4 — not a leap year.
Leap Years in a Range
Leap Years in the 2000s
All 25 leap years from 2000 to 2099. Click any year to check it above.
Frequently Asked Questions
Is 2024 a leap year?
Yes. 2024 is a leap year. It is divisible by 4 and not by 100, so it satisfies the leap year rule and has 366 days including February 29.
Is 2100 a leap year?
No. 2100 is divisible by 100 but not by 400, so it is not a leap year (the century exception). It will have only 365 days and no February 29.
How do you determine if a year is a leap year?
A year is a leap year if: (1) it is divisible by 4, AND (2) it is not divisible by 100, UNLESS (3) it is also divisible by 400. In code: isLeapYear = (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0.
Why was the leap year rule changed from the Julian calendar?
The Julian calendar added a leap day every 4 years without exception, making the average year 365.25 days — about 11 minutes too long. By 1582 the calendar had drifted 10 days ahead of the solar year. Pope Gregory XIII corrected this by skipping century leap years (except multiples of 400), giving an average year of 365.2425 days — accurate to within 26 seconds per year.
What is the next leap year after 2024?
The next leap year after 2024 is 2028. Leap years occur every 4 years in most cases (2024, 2028, 2032, 2036…), except around century years. You can use our Leap Year Calculator to find the next leap year after any year.
Was 1900 a leap year?
No. 1900 is divisible by 100 but not by 400, so it was not a leap year under the Gregorian calendar rules. This surprises many people who only remember the 'divisible by 4' rule.
Was 2000 a leap year?
Yes. 2000 is divisible by 400, so it was a leap year despite being a century year. It had 366 days including February 29.
What happens to people born on February 29?
People born on February 29 (called leaplings or leap-day babies) celebrate their birthday on that date only in leap years. In common years, they typically observe their birthday on February 28 or March 1, depending on local custom or legal convention. The probability of being born on Feb 29 is about 1 in 1,461.
What is a Leap Year?
A leap year is a calendar year that contains an extra day — February 29 — making it 366 days long instead of the usual 365. Leap years exist to keep the calendar year synchronized with the solar year (the time Earth takes to orbit the Sun), which is approximately 365.2422 days. Without the occasional extra day, the calendar would drift about one day every four years, shifting seasons by weeks over a century.
Leap Year Rules — The Three-Part Algorithm
The Gregorian calendar uses three rules to determine whether a year is a leap year:
- Divisible by 4: If a year is evenly divisible by 4, it is a leap year — unless Rule 2 applies.
- Divisible by 100 (century exception): If a year is evenly divisible by 100, it is not a leap year — unless Rule 3 applies.
- Divisible by 400: If a year is evenly divisible by 400, it is a leap year regardless of Rule 2.
Algorithm in pseudocode:
isLeapYear(year): if year % 400 == 0 → true (e.g., 2000, 2400) if year % 100 == 0 → false (e.g., 1900, 2100) if year % 4 == 0 → true (e.g., 2024, 2028) else → false (e.g., 2023, 2025)
| Year | ÷4? | ÷100? | ÷400? | Leap? |
|---|---|---|---|---|
| 2024 | Yes | No | No | Yes |
| 2023 | No | No | No | No |
| 1900 | Yes | Yes | No | No |
| 2000 | Yes | Yes | Yes | Yes |
| 2100 | Yes | Yes | No | No |
| 2400 | Yes | Yes | Yes | Yes |
Why Does February Have 29 Days?
February is the shortest month in the Gregorian calendar, a legacy of ancient Roman calendar reforms. The original Roman calendar had only 10 months (304 days), starting in March. When King Numa Pompilius added January and February around 713 BC, he ended up with February as the last month with the fewest days — the Romans considered even numbers unlucky, so months alternated between 29 and 31 days except for February, which had 28.
Julius Caesar's calendar reform in 46 BC — the Julian calendar — introduced the concept of the leap day on February 29. February was chosen for the extra day because it was already the "overflow" month at the end of the Roman year. Pope Gregory XIII's 1582 reform kept February as the leap-day month but refined when it occurs to prevent long-term calendar drift.
Historical Calendar Background
The Julian Calendar (46 BC)
Julius Caesar introduced the Julian calendar, which added a leap day every four years without exception. This was a huge improvement over the chaotic Roman calendar, but because the solar year is slightly less than 365.25 days, the Julian calendar gained about 11 minutes per year — amounting to one full day every 128 years.
The Gregorian Reform (1582)
By 1582, the Julian calendar had drifted about 10 days ahead of the solar year. Pope Gregory XIII corrected this by skipping October 5–14, 1582 (October 4 was followed by October 15), and introducing the century exception: century years (1700, 1800, 1900…) are not leap years unless also divisible by 400. This reduces the average year to 365.2425 days — accurate to within 26 seconds per year.
The Century Exception Explained
The solar year is 365.24219 days. A simple "÷4" rule gives 365.25 days on average — too long by about 11 minutes. Removing three leap years every 400 years (the century years not divisible by 400) brings the average down to exactly 365.2425 days, a much better approximation. This is why 1900 was not a leap year but 2000 was.
Leap Year Frequency & Patterns
In a 400-year Gregorian cycle, there are exactly 97 leap years out of 400 — giving an average year length of 365.2425 days. The pattern is:
- Most leap years occur every 4 years (e.g., 2024, 2028, 2032…).
- Century years skip the leap day (e.g., 2100, 2200, 2300).
- Every 400 years, a century year gets the leap day back (e.g., 2000, 2400).
- The gap between two leap years is almost always 4 years, but can be 8 years around century years (e.g., 1896 → 1904, skipping 1900).
Leap Day Birthdays (Leaplings)
People born on February 29 are sometimes called leaplings or leap-day babies. Statistically, about 1 in 1,461 people are born on Feb 29 (roughly 0.068% of the population). Famous leaplings include motivational speaker Tony Robbins (born February 29, 1960) and rapper Ja Rule (born February 29, 1976).
In non-leap years, leaplings typically celebrate their birthdays on either February 28 or March 1, depending on cultural convention and legal jurisdiction. Some countries, such as the UK, legally recognize February 28 as the leap-day birthday in non-leap years.
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