Check Common Year

A common year is a Gregorian calendar year with exactly 365 days – so February has 28 days instead of 29. Most years are common; only roughly 1 in every 4 is a leap year.

A year is a leap year if it is divisible by 4, with one exception: century years (divisible by 100) must also be divisible by 400 to qualify. So 1900 is common, but 2000 is a leap year.

No. The year check runs entirely in your browser with a few lines of arithmetic. No fetches, no analytics on the input.

Both are divisible by 4 and by 100, so both are century years. The extra rule says a century year must also be divisible by 400 to be a leap year. 2000 passes (2000 ÷ 400 = 5); 1900 fails (1900 ÷ 400 = 4.75).

Three yes/no rows – divisible by 4, by 100, and by 400 – so you can trace how the tool arrived at the verdict without doing the math yourself.

If you are scheduling a February 29 event or checking a contract that depends on a leap year, you often need to know the closest one before or after a given date. The tool finds them with a simple scan.

The tool always applies the Gregorian rule. The Julian calendar’s leap rule (every 4 years, no exceptions) was in use before October 1582 in Catholic countries and later elsewhere, so use a dedicated Julian calculator for genuinely historical work.

999,999 – a safety cap that keeps the “find nearest leap year” scans fast. A common year check itself is instant at any size; the cap just bounds the scan loop.

No. The tool requires a year ≥ 1 because the Gregorian and proleptic-Gregorian conventions disagree on whether a year zero exists. Add an astronomical-year converter if you need BC/BCE support.

After the page loads, yes. Everything is static HTML, CSS, and JS – disconnect Wi-Fi and keep checking.