Free Date Difference Calculator

Summary

A date difference calculator counts the time between two calendar dates. To use this one free and privately, pick a Start Date and an End Date. The page shows the number of days, the same gap in years, months and days, the weeks and the working days, all calculated in your browser with nothing uploaded. By default the count runs from the start date up to, but not including, the end date; tick Include the end date to count both.

The day count is the end date minus the start date, worked out on whole day numbers so time zones and daylight saving cannot shift it. Working days are the total minus the weekend days you select, Saturday and Sunday by default. For an exact age use the age calculator, and to charge interest for a number of days try the simple interest calculator.

Table of Use: Example Dates and Results

Every row was produced by the calculator’s own functions. The weekend is Saturday and Sunday unless stated.

Features

• Total days, with or without the end date, plus the same gap as weeks and days and, from 12 months up, as whole months.
• Calendar years, months and days that reverse the add-months panel exactly.
• Working Days and Weekend Days, with any combination of Sun to Sat as the weekend. A Show working days only option makes working days the headline figure.
• Reversed dates handled: if the end date is earlier, the page says so and still shows the gap.
• Copy places a text summary of the result on your clipboard.
• Add or Subtract Time by days, weeks, months, years or working days, answered with the weekday and full date.
• Today shortcuts for every date field, and dates from year 1 to 9999.

Know the limits: public holidays are never deducted, and the calculator works in whole days, not hours. To compare clock times between cities use the time zone converter, or run a countdown timer to a date.

How to Use the Date Difference Calculator

1. Choose the Start Date and the End Date, or press Today beside either.
2. Decide whether to tick Include the end date, and whether to tick Show working days only.
3. Under Weekend days, press the days that are your weekend. Saturday and Sunday are preselected.
4. Read the Difference, the years, months and days line, and the Working Days and Weekend Days boxes. Press Copy to save the summary.
5. For a new date, use Add or Subtract Time: set the Starting Date, press Add or Subtract, type a Number, pick a Unit and read the Result Date.

Nothing is submitted and nothing is uploaded: the calculation runs in your browser, which the Network tab in DevTools will confirm.

Who Can Use It

Project managers can size a schedule in working days, payroll and HR staff can count notice periods, and travellers can count nights. Students can find days left until an exam, and anyone can check what date an invoice falls due. To express days elapsed as a share of a period, use the percentage calculator.

Expecting a baby? Date maths for pregnancy lives in the pregnancy due date calculator and the ovulation calculator. To lay out the weeks on paper, print a month or year with the calendar generator. Years until a goal date can feed the retirement calculator.

FAQs

How do I count the days between two dates?

Enter a Start Date and an End Date. By default the count runs from the start date up to, but not including, the end date, so 5 to 9 October 2026 is 4 days, the same as 4 hotel nights. Tick Include the end date to count both the first and last day, which gives 5; use that for leave, events or contracts that say “from and including”.

How is the gap in years, months and days worked out?

It uses real calendar months, not an average month length. A month counts once the end date reaches the start date’s day of the month, or the last day of a shorter month. So 1 January to 1 March 2026 is 2 months, and 31 January to 28 February 2026 is 1 month. It is the exact reverse of adding months in the second panel.

How do I count working days between two dates?

The Working Days figure appears under the total. It excludes the weekend days you choose with the Sun to Sat buttons, Saturday and Sunday by default, so a six-day week needs only Sunday ticked. Public holidays differ by country and region and are not deducted, so subtract any holidays in your range yourself.

Why does 1 January to 31 December show 11 months and 30 days?

Because the end date is not counted by default. From 1 January 2026 to 31 December 2026 is 364 days, which is 11 months and 30 days, as 31 December is the last day of the year rather than the start of the next. Tick Include the end date and the result becomes 365 days, exactly 1 year.

What date is 90 days from today?

In Add or Subtract Time, press Today beside Starting Date, keep Add selected, type 90 and choose Days. The Result Date shows the weekday and full date. From Tuesday 6 October 2026 the answer is Monday 4 January 2027. Choose Working days as the unit to skip weekends instead: 30 working days from the same date is Tuesday 17 November 2026.

What is 31 January plus one month?

When the target month is shorter, the result is that month’s last day, so 31 January plus 1 month is 28 February 2026, or 29 February in a leap year such as 2028. Subtracting works the same way: 6 months before 31 August 2026 is 28 February 2026. Adding days or weeks never needs this adjustment.

Is my data sent anywhere?

No. Every date calculation runs in your browser, and nothing you enter is uploaded or stored. You can confirm it by opening the Network tab in your browser’s DevTools while you change a date: no request is made. Working with whole day numbers also means time zones and daylight saving cannot shift a result.