Advanced Leap Year Checker
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Leap Year Rules Explained
A leap year must satisfy one of the following conditions:
- The year is evenly divisible by 4 but not by 100
- The year is evenly divisible by 400
Why Leap Years Exist
Leap years keep our calendar in alignment with Earth’s revolutions around the Sun, adding about 0.25 days per year.
Historical Context
The Julian calendar introduced leap years in 45 BCE, refined to the current Gregorian calendar rules in 1582.
Special Cases
Years divisible by 100 are not leap years unless they’re also divisible by 400 (e.g., 2000 was a leap year, but 1900 wasn’t).