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Leap Year Checker, Is It a Leap Year

Is it a leap year? Type any year for a yes/no, the 4/100/400 rule worked out, Feb length, and the next leap year, browser-only

  • Runs locally
  • Category Calculator
  • Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.
2026 is not a leap year
Not divisible by 4, so it is a common year.
Why
Divisible by 4
no
Divisible by 100
no
Divisible by 400
no
Days in the year
365
Days in February
28
Previous leap year
2024
Next leap year
2028
2 years away
List leap years in a range
5 leap years
20282032203620402044

What this tool does

Free leap year checker that answers "is it a leap year?" for any year and shows the work. Type a year and you get an instant yes or no, the exact rule applied (divisible by 4, and either not divisible by 100 or divisible by 400), the number of days in that year (365 or 366), how many days February has (28 or 29), the previous and next leap years, and how many years until the next one. There is also a range mode that lists every leap year between two years, so you can copy a clean list for a calendar, a contract or a piece of code. The classic gotchas are handled correctly: 2000 is a leap year, but 1900 and 2100 are not, because a century year is only leap when it divides evenly by 400. Everything runs in your browser with one-click copy and a shareable link that reopens on the same year. 100% client-side, nothing is uploaded.

Tool details

Input
Numbers
The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output
Live result + Copy
The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy
Browser-side processing
The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share
Shareable URL state
Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget
Initial JS <= 9 KB
No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit
Calculator · Student
Category and role tags drive related tools, internal links, and quick fit checks.

How to use

  1. 1. Input

    Paste or drop your content into the tool panel.

  2. 2. Process

    Click the button. All processing is local in your browser.

  3. 3. Copy / Download

    Copy the result or download to disk in one click.

How Leap Year Checker fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

  • Getting a realistic range before a purchase, plan, workout, or schedule decision.
  • Comparing scenarios by changing one input at a time.
  • Turning rough assumptions into a number you can discuss.

Calculation checks

  • Double-check units, dates, rates, and rounding assumptions.
  • Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
  • Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

  1. 1 Age Calculator Calculate your exact age — years, months, days, hours. Compare two dates or count to a future date. Open
  2. 2 Days Until Date Calculator How many days until a date — plus weeks, months, business days, exact remaining, and the weekday it lands on Open
  3. 3 Add Days to Date Calculator Add or subtract days, weeks, months, and years from any date — plus a business-day mode that skips weekends. Runs entirely in your browser. Open

Real-world use cases

  • Settle a "is this year a leap year" argument fast

    Someone insists 2100 is a leap year because it divides by 4. Type 2100 in, and the tool shows divisible by 4 yes, by 100 yes, by 400 no, verdict common year, 365 days. The three little checkmarks end the debate without anyone having to remember the century rule from memory.

  • Plan a project schedule that spans February

    A deadline counted in days from late January can land a day off if February has 29 days instead of 28. Before you lock the dates, check whether the year is leap so you count February correctly. Pair it with the days-until-date-calculator to get the exact day count.

  • Pick test cases when coding a date function

    Writing your own leap-year check? Use this as the oracle. Feed it the classic traps, 2000 leap, 1900 not, 2024 leap, 2023 not, and the range mode for a quick list of expected leap years to assert against in your unit tests. The exported logic mirrors the standard formula.

  • Teach the 4-100-400 rule in class

    A teacher can put 1896, 1900 and 1904 on the board, run each through the checker, and let students see why 1900 breaks the every-four-years pattern. The range mode listing leap years from 1800 to 1900 makes the century skips visible at a glance.

  • Find a real Feb 29 birthday for a leapling

    Born on February 29 and want the next year you actually get the date? Enter your birth year, read the next leap year, and you know which year carries a genuine Feb 29 rather than the Mar 1 stand-in some systems use. Handy for booking a milestone birthday.

Common pitfalls

  • Thinking every fourth year is leap with no exceptions. The divide-by-4 rule alone wrongly marks 1900 and 2100 as leap. Century years need to divide by 400 too, which is why 2000 is leap but 1900 is not.

  • Assuming a century year ending in 00 is automatically not a leap year. The opposite over-correction. 2000 and 2400 are leap years because they divide by 400. Always run the 400 check before deciding a 00 year is common.

  • Forgetting that a leap year changes February and the year length. A leap year has 366 days and February has 29, so any day-count that crosses a leap February is off by one if you used 365 or 28 out of habit.

Privacy

Every check, the leap-year rule, the day counts and the range listing, is plain JavaScript running in your browser tab. No year you type ever leaves the page and nothing is logged. The one caveat: the shareable link encodes the year in the query string, so a link pasted into chat will record that year in the recipient server's access log. There is nothing sensitive about a year, but if you prefer, use the copy button on the range list instead of sharing the URL.

FAQ

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Made by Toolora · 100% client-side · Updated 2026-05-29