Leap year checker

Client

Apply Gregorian leap-year rules to any year from 1 through 9999. For date spans or weekday counts, try business days or date difference.

About Leap year checker

Test whether a calendar year is a leap year—Gregorian rules, computed locally. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.

How to use this page

Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.

2024 is a leap year.

Nearby workflows on Toolcore

  • ISO week number — ISO 8601 week number and Monday–Sunday bounds for any calendar date—local browser calculation. when units or numeric output should be checked on a related calculator.
  • Date difference — Calendar days between two dates—pair with the timestamp or unit tools as needed. when units or numeric output should be checked on a related calculator.
  • Unix timestamp converter — Epoch to date: seconds, milliseconds, ISO-8601, UTC and local time—in browser. when units or numeric output should be checked on a related calculator.
  • World clock & time zones — Compare IANA time zones side by side with the same instant—no server round-trip. when units or numeric output should be checked on a related calculator.

Common use cases

  • Verify whether February has 29 days for a given year.
  • Quick classroom check of century-year leap exceptions.

Common mistakes to avoid

  • Using divisible-by-4 only

    Years divisible by 100 are not leap years unless also divisible by 400.

FAQ

Which calendar system is used?

Standard Gregorian rules—same as most modern civil calendars.

Is data uploaded?

No. The check runs entirely in your browser.

More tools

Related utilities you can open in another tab—mostly client-side.