Number of Days Calculator

Created by Rijk de Wet
Reviewed by Adena Benn
Last updated: Oct 11, 2022

With the number of days calculator, you'll learn how many days there are between two dates in time! Stick around, and you'll quickly learn how to calculate the number of days between two dates of your choosing.

How to use the number of days calculator

The number of days calculator is easy to use and yet powerful in its features:

  1. If you have two dates, you can enter them into the From and To fields. The number of days between these two dates will be calculated and reported in the Time between field.
  2. If you want to determine the date of the day that's x days after a starting date, then enter that date in From and the number of days in Time between — you'll find the end date in the To field.
  3. The same goes for going backward in time x days from an end date — enter the number of days in Time between and the end date in To.
  4. If you want to see how your number of days translates to weeks, months, and years, you can change the unit of Time between to have it calculated for you!

If you want to get more precise, you can activate our Advanced mode at the bottom and have the option to:

  • Include or exclude the end date;
  • Count only business days (Monday to Friday and not Saturday or Sunday); and
  • Count only certain days of the week.

How do I calculate the number of days between two dates?

It's a simple question with difficult implications — how many days are there between two dates? It gets more difficult the further these two dates are from each other in time. Let's look at some examples and see what we mean!

🔎 In all the example calculations below, we exclude the end date. If we wish to include the end date, we'd need to add 1 day to each result.

Same month and same year

If both dates are in the same month of the same year, you can subtract the dates' calendar day numbers from each other. For example, April 4, 2022 and April 17, 2022 are 17 − 4 = 13 days apart.

Same year but different months

If both dates are in the same year but not the same month, you can work out the number of days from January 1 (of that year) to both your dates and subtract these two differences. To do that, you need the number of days in each month of that year (remember to check for leap years).

For example, if we want to figure out how many days are between May 17, 2022, and July 8, 2022, we'd work them both back to January 1 of 2022:

  • There are 31 + 28 + 31 + 30 + 17 = 137 days from January 1 to May 17 in 2022. How'd we get there? Well, January and March each have 31 days, April has 30, and February has 28. We add them together and add the 17 of May 17 to get the 137 days.
  • The same for July 8: There are 31 + 28 + 31 + 30 + 31 + 30 + 8 = 189 days from January 1 to July 8 in 2022.
  • The difference between these two time differences (189 − 137 = 52 days) is the number of days between May 17 and July 8, 2022.

Different years

If there are one or more years between two dates, we should work out two things:

  • For the start date, we need the number of days between itself and December 31 of that year. Here, we must include the end date (so add 1 day).
  • For the end date, we need the number of days between January 1 of that year and itself (excluding the end date).
  • We also need to know how many complete calendar years there are between the two dates.

Example: let's work out the number of days between September 17, 1997, and December 1, 1999.

  • September 17, 1997, to December 31, 1997, is 105 days, and 106 days with the end date included.
  • January 1, 1999, to December 1, 1999, is 334 days.
  • There is one complete calendar year (1998) between our dates, contributing another 365 days to the day count.

So, the grand total of number of days between September 17, 1997 and December 1, 1999 is 106 + 334 + 365 = 805 days.

And that's it — now you know how to calculate the number of days between any two dates!

If the number of days calculator didn't help you count the days, then perhaps you might be interested in our other day counting calculators:


How many months have 28 days?

Only one, and that's February. That's only if the year in question is not a leap year. If the year is a leap year, then February would have 29 days.

How many work days are in a year?

On average, there are 261 work days per year, but it varies slightly every year. 2021 had 261 business days. 2022 has 260 working days, and so will 2023. 2024 is a leap year with an extra day, so it'll have 262 working days. Remember that these numbers do not account for public holidays, as those vary by country.

How many days are in a month?

It depends on which month. January, March, May, July, August, October, and December each have 31 days. April, June, September, and November each have 30 days. February typically has 28 days but has 29 days in a leap year. On average, there are 30.42 days in a month (as 365 days / 12 months = 30.41666 days per month).

Rijk de Wet
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