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 calculation follows these rules:

Where:

• \( y \) — The year to check
• \( \% \) — Modulo operation (remainder after division)

Explanation: A year is a leap year if it's divisible by 4, but not divisible by 100 unless it's also divisible by 400.

3. Importance of Leap Years

Details: Leap years maintain calendar accuracy. Without them, seasons would gradually shift over time. The Gregorian calendar system adds a leap day every 4 years with exceptions to maintain precision.

4. Using the Calculator

Tips: Enter any year (1-9999) to check if it's a leap year. The calculator implements the standard Gregorian calendar rules.

5. Frequently Asked Questions (FAQ)

Q1: Why do we skip some leap years?
A: Years divisible by 100 are not leap years unless they're also divisible by 400. This corrects for the slight overcompensation of adding a leap day every 4 years.

Q2: Was 2000 a leap year?
A: Yes, because although it's divisible by 100, it's also divisible by 400.

Q3: Will 2100 be a leap year?
A: No, because it's divisible by 100 but not by 400.

Q4: How accurate is this system?
A: The Gregorian calendar averages 365.2425 days per year, very close to the actual solar year of 365.2422 days.

Q5: When was the leap year system introduced?
A: The Gregorian calendar with its current leap year rules was introduced in 1582.