1. What is a Leap Year?

A leap year is a year containing one additional day (February 29) to keep the calendar year synchronized with the astronomical year. Without leap years, our calendar would gradually drift out of alignment with the Earth's revolutions around the Sun.

2. How Does the Calculation Work?

The leap year calculation follows this formula:

Where:

• \( year \) — The year to check (positive integer)
• \( \% \) — Modulo operator (remainder after division)

Explanation: A year is a leap year if it's divisible by 4, except for years that are divisible by 100 unless they're also divisible by 400.

3. Importance of Leap Years

Details: Leap years maintain the alignment of our calendar with Earth's orbit around the Sun (approximately 365.2422 days). Without correction, seasons would gradually shift in the calendar.

4. Using the Calculator

Tips: Enter any year (positive integer) to check if it's a leap year. The calculator will evaluate the standard Gregorian calendar rules.

5. Frequently Asked Questions (FAQ)

Q1: Why do we skip some century years?
A: Years divisible by 100 are not leap years unless also divisible by 400 (e.g., 2000 was a leap year but 1900 was not).

Q2: When was the leap year system introduced?
A: The Gregorian calendar introduced these rules in 1582, replacing the Julian calendar which had simpler rules.

Q3: Are there exceptions to these rules?
A: Some countries adopted the Gregorian calendar at different times, causing historical date discrepancies.

Q4: How accurate is this system?
A: The Gregorian calendar accumulates about 1 day error every 3236 years compared to astronomical years.

Q5: Do other calendars have leap years?
A: Yes, lunar and lunisolar calendars have different intercalation methods to stay synchronized.