Leap Year Checker - Is It a Leap Year?

Leap years exist to keep our calendar aligned with Earth's orbit around the Sun. Since Earth takes about 365.25 days to complete one orbit, we add an extra day every 4 years to account for the accumulated quarter-day difference. However, the rule has exceptions: years divisible by 100 are not leap years unless they're also divisible by 400. This is why 2000 was a leap year, but 1900 was not. This complex system ensures our calendar stays accurate over centuries.