Date to Date Calculator
Pick a start date and an end date and we will tell you how many days apart they are, and the same gap in weeks, months and years.
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The formula
Days between = end date - start date (counted in whole calendar days).
Counting days between two dates
We count whole calendar days. From 1 January to 25 December is 358 days. If you want the end date included as well (counting both the first and last day), add one.
You can enter the dates in either order. The calculator always measures the gap, so you do not need to work out which comes first.
Years, months and days
Alongside the plain day count, you get the gap written as years, months and days, for example 11 months and 24 days. This is the form most people use when they say "how long has it been?".
Typical uses
- How many days until a holiday, exam or wedding
- The length of a notice period or a contract
- How long a project actually took
- Days since a last event, such as an invoice date
If you only need working days, the business days calculator skips weekends and any holidays you list.
Examples to check
Type these into the calculator above to see how it behaves. Every result below was produced by the same calculator code that runs on this page.
| What you enter | What you get |
|---|---|
| Days between two dates; Start date: 2026-01-01; End date: 2026-12-25 | Difference: 358 days |
| Days between two dates; Start date: 2026-03-15; End date: 2026-10-03 | Difference: 202 days |
| Days between two dates; Start date: 2024-02-28; End date: 2024-03-01 | Difference: 2 days |
Date to Date Calculator: frequently asked questions
How do I include both the start and end date in the count?
Add one day to the result. A trip from the 1st to the 7th is 6 days apart but covers 7 calendar days.
How many weeks is that?
Divide the days by 7. The calculator also shows whole weeks and leftover days for you.
Does the calculator count the start date?
No. Adding 1 day to 1 March gives 2 March. The start date itself is day zero.
What happens when I add a month to the 31st?
We move to the last day of the shorter month. Adding one month to 31 January gives 28 February (29 in a leap year), which matches how most calendars and spreadsheets behave.
Does it take leap years into account?
Yes. Calculations use real calendar dates, including leap days and the different lengths of months.
Is what I enter in this calculator saved or sent anywhere?
No. The calculation runs in your browser, so what you enter is not sent to our servers. We only count, anonymously, whether a tool ran successfully.
Last reviewed: October 3, 2026