Date Calculator

Count days between two dates, or add days to a date.

Result

Enter values and press Calculate to see the result.

Formula

days=end−start\text{days} = \text{end} - \text{start}

Dates are counted as whole calendar days, including leap days (the end date is not counted twice).

How to use this calculator

  1. Choose the mode and pick the dates.
  2. The difference counts from the start date up to (not including) the end date.

Worked example

Days from 1 January to 25 December 2026

25 December is day 359 of 2026, and 1 January is day 1.

So there are 358 days between them: 51 weeks and 1 day.

Frequently asked questions

Are leap years handled?

Yes — every date is converted to an exact calendar day count.

Does it count the end date?

No. From Monday to Tuesday is 1 day. Add 1 if you want to include both ends.