When is Leap Year?

Welcome to the Leap Year Checker, a comprehensive tool to find out when is the last and next leap year, check if any year is a leap year, and understand the rules behind leap years with interactive visualizations. Whether you are planning ahead, curious about history, or studying calendar systems, this tool provides everything you need to know about leap years.

What is a Leap Year?

A leap year is a calendar year that contains an additional day compared to a common year. In the Gregorian calendar (the calendar most widely used today), a leap year has 366 days instead of the usual 365, with the extra day added to February as February 29th, also known as Leap Day.

The purpose of leap years is to keep our calendar synchronized with Earth's orbit around the Sun. Earth takes approximately 365.2422 days to complete one orbit (a solar year). Without leap years, our calendar would gradually drift out of alignment with the seasons by about 24 days every century.

Leap Year Rules

The Gregorian calendar uses a specific set of rules to determine which years are leap years:

Simple Summary

• Most years divisible by 4 are leap years (2024, 2028, 2032...)
• Century years (ending in 00) are NOT leap years, UNLESS divisible by 400
• Examples: 1900 was NOT a leap year, but 2000 WAS a leap year

How to Use This Tool

1. View Current Status: See whether the current year is a leap year and when the next one occurs
2. Check Any Year: Enter a year (1-9999) to instantly check if it's a leap year
3. Use Quick Examples: Click on preset years to see the leap year rules in action
4. Explore the Timeline: Browse through leap years visually on the interactive timeline
5. Learn the Rules: View the step-by-step decision flowchart showing how leap years are determined

Understanding Leap Year Results

When you check a year, you will receive:

• Leap Year Status: Whether the year is or isn't a leap year
• Detailed Explanation: The specific rule that determines the result
• Decision Path: Step-by-step breakdown of how the determination was made
• February Days: Whether February has 28 or 29 days
• Total Year Days: Whether the year has 365 or 366 days
• Nearby Leap Years: The previous and next leap years

Why Century Years Are Special

The 400-year rule exists because the solar year is not exactly 365.25 days—it's closer to 365.2422 days. If we added a leap day every 4 years without exception, we would gain about 3 extra days every 400 years. By skipping leap years in century years not divisible by 400, the calendar stays more accurate.

Century Year Examples

• 1700, 1800, 1900: NOT leap years (divisible by 100, not by 400)
• 2000: IS a leap year (divisible by 400)
• 2100, 2200, 2300: Will NOT be leap years
• 2400: Will be a leap year (divisible by 400)

Leap Day Traditions

February 29th has inspired many traditions and superstitions around the world:

• Leap Day Babies: People born on February 29th are called "leaplings" or "leap year babies." They typically celebrate on February 28th or March 1st in non-leap years.
• Bachelor's Day: In some countries, there is a tradition that women may propose marriage on Leap Day.
• Leap Year Festivals: Several towns, particularly Anthony, Texas/New Mexico (the self-proclaimed "Leap Year Capital of the World"), hold special celebrations.

Frequently Asked Questions

What is a leap year?

A leap year is a year with 366 days instead of the usual 365. The extra day, February 29th, is added to keep our calendar in alignment with Earth's revolutions around the Sun. Earth takes approximately 365.25 days to orbit the Sun, so every 4 years we add an extra day to account for the accumulated quarter days.

How do you determine if a year is a leap year?

A year is a leap year if: (1) It is divisible by 4, AND (2) If divisible by 100, it must also be divisible by 400. For example, 2024 is a leap year (divisible by 4, not by 100). 1900 was not a leap year (divisible by 100 but not 400). 2000 was a leap year (divisible by 400).

When is the next leap year?

The next leap year after 2024 is 2028. Leap years typically occur every 4 years, with exceptions for century years not divisible by 400. After 2028, the following leap years will be 2032, 2036, 2040, and so on.

Why was 2000 a leap year but 1900 was not?

The Gregorian calendar has a special rule for century years (years ending in 00). While most years divisible by 4 are leap years, century years must also be divisible by 400 to be leap years. 2000 ÷ 400 = 5 (whole number), so 2000 was a leap year. 1900 ÷ 400 = 4.75 (not whole), so 1900 was not a leap year.

What happens on February 29th (Leap Day)?

February 29th, known as Leap Day, only occurs during leap years. People born on this day are called "leaplings" or "leap day babies." They typically celebrate their birthday on February 28th or March 1st in non-leap years. Leap Day has various cultural traditions around the world.

How many leap years are there in a century?

There are typically 24 or 25 leap years in a century. Most centuries have 24 leap years because the century year (like 1900, 2100) is usually not a leap year. However, centuries where the year is divisible by 400 (like 2000) have 25 leap years.

Additional Resources

• Leap Year - Wikipedia
• Gregorian Calendar - Wikipedia