Leap Year Calculator to Check One or Generate Range of Years

Leap Year Calculator Sign

This free online date calculator will check to see if the entered year is leap year according to the Gregorian calendar.

Or, if you enter a starting year and an ending year, the calculator will generate a list of leap years for the given range (e.g., list of leap years since 1900). And not only will the list include the dates of each leap day, but it will also include the day of the week that each leap day falls on.

And finally, if the start year is a leap year, and a special occasion (birth, wedding, etc.) occurred on February 29th of that year, the calculator will also report how many times you were able to celebrate on the anniversary date.

In case you're wondering, as of the last leap year was , and the next leap year is .

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Leap Year Calculator

Check to see if a given year is a leap year, or generate a future or past leap years list for a range of years.

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Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Check year:Check/start year:Check year or range start year:Check year or range start year:

Check year or range start year:

Enter the 4-digit year you would like to check. Or, if you want the calculator to generate list of leap years, consider the year entered on this line to be the starting year for the range.

End year:Ending year:Range end year:Range end year:

Range end year (optional):

If you want the calculator to generate list of leap years between a range of years, consider the year entered on this line to be the ending year for the range. Otherwise, leave this field blank if you are only checking to see whether or not a specific year is a leap year.

Leap year?Leap year?Is start year a leap year?Is start year a leap year?

Is start year a leap year?

Based on the entered year to check (or start year), this field will report whether or not that year is a leap year (Yes or No).

Anniv years:Anniversary yrs:Leap years from start year to now:Number of leap years from start year to now:

Number of leap years from start year to now:

If the entered start year is a leap year, and is earlier than the present year, the leap year calculator will count how many times a February 29th has occurred from the start year through the present date.

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

Help and Tools

Learn

What leap years are, how they are determined, and why they are needed.

What is a Leap Year?

A leap year is one that contains 366 days versus a normal year that contains 365 days. This extra leap day is added to February, meaning the month of February has 29 days in a leap year whereas February in a non-leap year only has 28 days.

When is a Leap Year?

The extra day (February 29) is added to years where:

  • The number 4 divides into the year evenly but the number 100 does not.
  • Or, the number 400 divides into the year evenly.

How to Calculate Leap Year

To illustrate how to calculate a leap year using the above formula, we'll use three example years: 2000, 2019, and 2020.

2000: Since 4 does divide into 2000 evenly (2000 ÷ 4 = 500), but so does 100 (2000 ÷ 100 = 20), at first glance you might not think that 2000 is a leap year. However, since 400 does divide into evenly (2000 ÷ 400 = 5), 2000 is a leap year after all.

2019: Since 4 does not divide into 2019 evenly (2019 ÷ 4 = 504.75), 2019 is not a leap year.

2020: Since 4 does divide into 2020 evenly (2020 ÷ 4 = 505) and 100 does not divide into it evenly (2020 ÷ 100 = 20.2), 2020 is a leap year.

If you want to calculate leap year in Excel, here is one you can do it:

AB
1YearLeap Year? (Formula)
22000=OR(
  MOD(A2,400)=0,
  AND(
    MOD(A2,4)=0,
    MOD(A2,100)>0
  )
)

Using the earlier example years, and filling the formula down Column B, here is what the spreadsheet would look like:

AB
1YearLeap Year?
22000TRUE
32019FALSE
42020TRUE

Why Do We Need Leap Years?

The reason adding an extra day every four years (with some exceptions) is needed, is because it takes the earth roughly 365.24 days to travel around the sun (a solar year), whereas as the Gregorian calendar is based on a 365-day year.

Since a solar year is different from a Gregorian year, if we didn't add leap days to the calendar periodically, the calendar year would continually fall further and further behind the solar year -- causing our seasons to get out of whack.

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.