Reference
Every year from 2000 to 2100, organized by decade. A ✓ marks each leap year — click any year for the full explanation.
Divisible by 4, except century years, which need to be divisible by 400. That single exception is why 2000 has a ✓ above but 1900 and 2100 do not, despite all three dividing evenly by 100.
Need a year outside this range, or want the day-of-week for a specific date instead? See the Leap Year Checker or Day of the Week Finder.