Skip to content
ENExplore Calculators

Leap Year Checker Calculator

Work out leap year checker instantly with clear inputs, formula shown and shareable results.

About Leap Year Checker Calculator

A Gregorian year is a leap year if divisible by four, except centuries, unless divisible by 400. So 2000 was a leap year but 1900 and 2100 are not. 2026 is not - the next is 2028. The rule gives an average year of 365.2425 days against the true tropical year of 365.24219, an error of one day in about 3200 years.

Formulas

Gregorian rule

leap if divisible by 4, and not by 100 unless also by 400

Average year length

365.2425 days

Worked example

With the default values below, Leap Year Checker Calculator returns Days In That Year of 365. Change any input above and every figure here is recalculated in your browser.

Inputs used

Year to checkaccepts 1–4,000
2,026
Years ahead to scan for the next leap yearaccepts 1–10,000
10

Results

Days In That Year
365 days
Is It A Leap Year?
No - 365 days
Next Leap Year
2,028
Leap Years In The Scanned Window
2

Step by step

  1. 1Values used
  2. 2Gregorian rule
  3. 3Average year length
  4. 4Days In That Year= 365 days
  5. 5Is It A Leap Year?= No - 365 days
  6. 6Next Leap Year= 2,028
  7. 7Leap Years In The Scanned Window= 2

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why was 1900 not a leap year?

Because the century exception applies: divisible by 100 but not by 400, so it was skipped to keep the calendar aligned with the seasons.

Will 2100 be a leap year?

No. It is divisible by 100 but not 400, so February will have 28 days - the first skipped leap year since 1900.

Related Calculators

Leap Year Checker Calculator – Calculate Days In That Year