TinySandyFree Online Tools

Date Difference Calculator

Pick two dates and see the gap as years, months and days, as a total number of days and weeks, and, if you like, as business days that skip Saturdays and Sundays. A second mode starts from one date and adds or subtracts years, months, weeks and days, giving the resulting date and its weekday. It is useful for deadlines, notice periods, project plans and warranty dates.

Date & Time Runs in your browser

Find the Time Between Two Dates

Dates are calendar dates, so there are no time-zone or daylight-saving effects. “Days between” excludes the end date unless you tick the include option. Business days are Monday to Friday and ignore public holidays.

How to Use the Date Difference Calculator

  1. Choose whether to find a difference or to add or subtract time.
  2. Pick the start date and the end date (or the years, months, weeks and days to add or subtract).
  3. Tick Include the end date for inclusive counting and business days if you need working days.
  4. Press Calculate and read the result and the working.

About This Tool

Project managers counting working days, HR and legal staff working out notice periods, students planning revision, and anyone asking how long until or since a date.

Input: Dates  ·  Output: Duration.

Features and Limitations

Features

  • Years, months, days, total days and weeks in one view.
  • Optional inclusive end date.
  • Business days (Mon–Fri) and weekend days.
  • Add or subtract years, months, weeks and days.
  • Handles leap years and month ends.

Limitations

  • Public holidays and regional weekends are not excluded from business days.
  • Dates must be between the years 1 and 9999, and use the Gregorian calendar.
  • No time of day is involved: use the Time Duration Calculator for hours and minutes.
  • Results are computed in your browser; nothing you enter is sent to a server.

Example

From 15 January 2024 to 20 March 2025: 1 year, 2 months, 5 days; 430 days in total (61 weeks and 3 days), of which 308 are business days. Adding 90 days to 15 January 2024 gives Sunday, 14 April 2024.

Frequently Asked Questions

Does the calculation include the end date?

By default no: 1 January to 31 January is 30 days, the normal “days between” rule. Tick “Include the end date” to count both ends, which gives 31 days. Use it for leave periods, hotel nights excluded, and inclusive ranges.

How are business days counted?

Every Monday, Tuesday, Wednesday, Thursday and Friday from the start date up to (but not including) the end date is counted, or including the end date if that option is ticked. Public holidays are not removed.

What happens when I add a month to 31 January?

Months are added first and the day-of-month is kept where possible. If the target month is shorter, the date moves to that month’s last day, so 31 January plus 1 month is 28 February (29 in a leap year).

How do I calculate days between two dates by hand?

Convert each date to a running day number and subtract. This tool uses the number of days since 1 January 1970, which accounts for leap years automatically.

What if my start date is after my end date?

The dates are swapped and the difference is shown as a positive amount, with a note saying so.

Related Tools

More like this: all Date & Time tools, all Calculators tools or the TinySandy home page.