Date Difference Calculator

Calculate days, weeks and months between two dates, or add and subtract days — free online.

About

About the Date Difference Calculator

Calculates the exact number of days, weeks and months between two dates, and lets you add or subtract time from any date to find the resulting date.

Project managers use it to count working days before a deadline, while HR and payroll staff use it to work out exact day counts for leave or contracts. It's one of many free calculators on Toolapt, and like every tool here, it's free to use with no sign-up and no limit on how many times you run it.

Choose what to view about this tool

Guide

Using the Date Difference Calculator

  1. 1

    Step 1

    Pick a start date and an end date to compare.

  2. 2

    Step 2

    Click "Compare dates" to see the total days, weeks, months and a weekday/weekend breakdown.

  3. 3

    Step 3

    Further down, pick a date to start from and enter how many days, weeks, months or years to add or subtract.

  4. 4

    Step 4

    Click "Calculate date" to see the resulting date, or Copy to copy it.

  • Shows the gap between two dates in days, weeks, whole months and hours all at once, not just one unit
  • Breaks total days down into weekdays and weekend days
  • Automatically swaps the two dates and tells you if the end date was actually earlier
  • Also adds or subtracts days, weeks, months or years from any date, in the same tool
  • Works entirely in your browser — no installs and no sign-up
  • Free to use, with no limit on how many times you run it
  • Fully responsive, so it works just as well on a phone as on a desktop

Project managers

Project managers use the Date Difference Calculator for working out how many working days are left before a deadline.

HR and payroll staff

HR and payroll staff use the Date Difference Calculator for counting the exact number of days between a start date and an end date for leave or contracts.

Event planners

Event planners use the Date Difference Calculator for finding what date falls a set number of weeks or months before or after a fixed event date.

Anyone with a deadline

Anyone with a deadline uses the Date Difference Calculator for finding out exactly how many days are left, or what date a set number of days from now falls on.

Examples

Date Difference Calculator examples

2 worked examples

01

Days until a deadline

1 January 2026 to 27 September 2026 is 269 days, or 38 weeks and 3 days.

02

Adding time to a date

Adding 90 days to 1 June 2026 lands on 30 August 2026.

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FAQ

Frequently asked questions

Quick answers to common questions about the Date Difference Calculator.

What does the Date Difference Calculator do?

It calculates the number of days, weeks and months between two dates, and separately lets you add or subtract time from any date to find the resulting date.

Is the Date Difference Calculator free to use?

Yes. It's free, with no sign-up, no watermark and no limit on how many times you use it.

Is my input safe when I use this tool?

Yes. The dates you pick are processed entirely on your own device — nothing is sent to a server.

What happens if I pick an end date earlier than the start date?

The calculator automatically swaps the two dates so the difference is always a positive number, and lets you know the dates were swapped.

Does it count weekdays and weekends separately?

Yes. Alongside the total day count, the result breaks the total down into weekdays (Monday to Friday) and weekend days.

Can I add months or years instead of days?

Yes. The second part of the tool lets you add or subtract days, weeks, months or years from any date you pick.

Can I use the Date Difference Calculator on my phone?

Yes. The page is fully responsive and works on mobile, tablet and desktop browsers alike.

Does the Date Difference Calculator have any limitations?

It's built for everyday date calculations. Extremely unusual calendar edge cases aside, results are accurate and instant for any date range.

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