Leap Year Checker

What is a leap year?

A leap year is a year with 366 days instead of the usual 365, adding an extra day — February 29 — to keep the calendar aligned with Earth's orbit around the Sun. A full orbit takes about 365.2422 days, so without an occasional extra day the calendar would slowly drift out of sync with the seasons. The Gregorian calendar adds that extra day in most years that are divisible by 4.

How is a leap year calculated?

The Gregorian rule combines three simple checks. A year is a leap year if it passes them, and a common (365-day) year if it does not:

1. If the year is divisible by 4, it is a candidate for a leap year.
2. But if it is also divisible by 100, it is normally not a leap year (these are the century years like 1900 and 2100).
3. Unless it is divisible by 400 as well — then it is a leap year after all, such as 2000.
4. Any year not divisible by 4, like 2023, is a common year with 365 days.

How to check if a year is a leap year

The checker works the moment you type — there is nothing to install:

1. Enter the year you want to check in the input, or click Current year to load this year.
2. Read the badge to see whether it is a leap year, plus a one-line explanation of the rule that applies.
3. Review the details — days in the year, days in February, and the previous and next leap years.
4. Click Copy to grab the result, or Clear to start over.

Why use this leap year checker?

• Instantly answers whether any year — past, present, or future — is a leap year.
• Explains the result with the exact divisible-by-4, century, and divisible-by-400 rule.
• Shows the total days in the year and whether February has 28 or 29 days.
• Lists the previous, next, and upcoming leap years at a glance.
• Handles tricky century years like 1900 (not a leap year) and 2000 (a leap year) correctly.
• Runs entirely in your browser — nothing you enter is uploaded or stored.

Frequently asked questions