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Date Difference Calculator

Count the days between two dates, including weeks, business days (Mon–Fri) and the difference in years, months and days.

Updated 7 October 2026 By

Runs in your browser Free · No sign-up

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How to use the Date Difference Calculator

  1. Choose a start and an end date.
  2. Tick “Include end date” if both days should count.
  3. Read the total days, weeks and business days.

About this tool

How many days until a deadline, a holiday or the end of a contract? Pick two dates to get the exact difference, optionally including the end date, plus the number of working days.

  • Private: your data is processed on your device and never uploaded.
  • Free with no account, limits or watermarks.
  • Fast: results appear instantly, even offline once the page has loaded.

What the Date Difference Calculator does

The date difference calculator counts the number of days between two dates and also shows the result in weeks, in years, months and days, in hours and as business days (Monday to Friday). It is the quickest way to answer questions like “How many days until my holiday?” or “How long was the project?”.

You decide whether the end date is included. Leave it unchecked for durations and deadlines — from Monday to Friday is 4 days. Check it when both days count, such as a hotel booking from the 1st to the 5th that you want to count as 5 days, or a leave request.

If the start date is after the end date, the tool simply swaps them, so you always get a positive result. Everything is calculated in your browser.

When to use it

  • Deadlines and notice periods

    Count the days until a contract ends, a payment is due or a notice period expires.

  • Holidays and events

    See how many days and weeks are left until a trip, a wedding or an exam.

  • Projects and work time

    Measure the length of a project or estimate business days for planning.

  • Pregnancy, training and habits

    Track how many days or weeks have passed since a start date.

Tips for the best results

  • Business days exclude Saturdays and Sundays only. Public holidays differ by country and region, so subtract them yourself.
  • Use “Include end date” when you count calendar days that are both used, for example days of leave.
  • The years-months-days result follows the calendar: from 31 January to 28 February is 28 days, but counted as 0 months and 28 days.
  • To count back from today, set the end date to today and the start date to the past event.

How the Date Difference Calculator works

Both dates are converted to midnight UTC, and the difference in milliseconds is divided by the length of a day. Using UTC means daylight saving changes cannot add or remove an hour and turn into an extra day.

Business days are counted by stepping through every day of the period and skipping Saturdays and Sundays. Weeks are the total days divided by seven, shown with one decimal place.

The breakdown into years, months and days uses the same calendar method as our age calculator, borrowing days from the previous month when needed.

Frequently asked questions

Are bank holidays excluded from business days?

No. Business days count Monday to Friday only. Bank holidays differ between England, Scotland, Wales and Northern Ireland, so subtract them yourself if needed.

Should I include the end date?

Include it when both the first and the last day count, for example for a hotel stay or a holiday from Monday to Friday.

How many days are there between two dates?

Enter the start and end date: the large number is the count of days between them, without the end date unless you check “Include end date”.

How do I count working days?

Look at “Business days”, which counts Monday to Friday. Remove public holidays that fall in the period manually.

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