Check whether any year is a leap year, see the divisible-by-4, 100 and 400 rule applied step by step, and find the leap years around it and February's length. Runs entirely in your browser — your numbers never leave this device.
| Year | Type | February |
|---|---|---|
| 2021 | Common year | 28 days |
| 2022 | Common year | 28 days |
| 2023 | Common year | 28 days |
| 2024 | Leap year | 29 days |
| 2025 | Common year | 28 days |
| 2026 | Common year | 28 days |
| 2027 | Common year | 28 days |
| 2028 | Leap year | 29 days |
| 2029 | Common year | 28 days |
| 2030 | Common year | 28 days |
| 2031 | Common year | 28 days |
The rule keeps the calendar aligned with Earth's orbit of about 365.2422 days: a leap day every 4 years overshoots slightly, so century years skip it — unless they are divisible by 400, like 2000, which was a leap year after all.
| Year | ÷4 | ÷100 | ÷400 | Verdict |
|---|---|---|---|---|
| 1900 | Yes | Yes | No | Not a leap year |
| 2000 | Yes | Yes | Yes | Leap year |
| 2024 | Yes | No | No | Leap year |
| 2026 | No | No | No | Not a leap year |
| 2028 | Yes | No | No | Leap year |
| 2100 | Yes | Yes | No | Not a leap year |
Enter a year and the calculator applies the Gregorian leap rule in its three steps and shows each test: is the year divisible by 4? By 100? By 400? The rule exists because Earth's orbit takes about 365.2422 days, not 365.25: a leap day every four years (the Julian rule) overcorrects by about 3 days every 400 years, so the Gregorian calendar skips the leap day in century years — except when the century is itself divisible by 400, which is why 2000 was a leap year but 1900 was not, and 2100 will not be.
Alongside the verdict you get the facts that depend on it: how many days February has in that year, whether the year runs to 365 or 366 days, and the previous and next leap years. A table of the surrounding eleven years shows the roughly four-year rhythm and where the century rule will eventually break it. The next break is close enough to matter for long-lived software and records: after 2096, the next leap year is 2104, an eight-year gap, because 2100 is skipped.
Leap status quietly changes other calculations — February spans in the Days Between Dates calculator, day-of-year counts after February, and 29 February birthdays in the Age Calculator — and every one of those tools uses this same rule, so a verdict here explains a result there.
A year is a leap year if it is divisible by 4, except century years, which are leap years only if divisible by 400. So 2024 (÷4) is leap, 1900 (÷100 but not ÷400) is not, and 2000 (÷400) is. The three tests are shown step by step for every year you check.
A leap day every 4 years assumes a 365.25-day year, but the true figure is about 365.2422 days. The 0.0078-day yearly excess grows to about 3 days per 400 years, and skipping three century leap days per 400 years — 1700, 1800, 1900 skipped; 2000 kept — cancels it almost exactly.
2028. Leap years normally arrive every four years (2024, 2028, 2032…), and the calculator shows the previous and next leap years for any year you enter. The one irregularity to watch: 2100 is skipped by the century rule, so 2096 is followed by 2104 — an eight-year gap.
29 — the leap day is 29 February. In a common year February has 28. The calculator shows February's length for the year you check, and the surrounding-years table shows it for the decade either side.
The Gregorian calendar has no year 0 — 1 BC is followed by AD 1 — but the divisibility rule is applied to year numbers directly, which is the standard convention for modern dates and the one every tool on this site uses consistently. All practical years (1800–2400 and well beyond) are unaffected by the question.
No. It runs in your browser; nothing is uploaded or recorded.
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