Date Difference Calculator
Find the exact difference between two dates and add or subtract days.
By Syed Mubashir Ali · Last updated
How to Use Date Difference Calculator
- 1Pick a start date and an end date. Both default to today and 30 days from today.
- 2Read the gap in total days, in weeks and days, in months and days, and in years, months and days.
- 3If the end date is before the start date, the total shows as a negative number of days.
- 4Tick 'Include the end date' to count both the first and the last day, and 'Skip US federal holidays' to take them out of the working-day count. Tick 'Saturday is a working day' for a six-day week.
- 5Under 'Your own days off', type company or local holidays one per line (2026-12-24 Christmas Eve, or 24/12/2026). They come out of the working days and the business-day sums, and the share link keeps them.
- 6Choose how dates are shown: written out in full, DD/MM/YYYY, MM/DD/YYYY or YYYY-MM-DD.
- 7To find a date in the future or past, use the 'Add or Subtract Time' panel: choose a base date, Add or Subtract, then enter years, months, weeks and days, or switch to business days. The answer updates as you type.
- 8Copy, print or share the result with the buttons under it; a shared link keeps your dates.
Frequently Asked Questions
How many days are there between two dates?
Enter both dates and read 'Total days'. For example, 15 January 2026 to 4 July 2026 is 170 days: 24 weeks and 2 days, or 5 months and 19 days.
Is the end date included?
Not unless you ask. By default the count is the number of days from the start date to the end date, the way you'd count nights in a hotel: Monday to Friday is 4 days. Tick 'Include the end date' to count both the first and last day (say, the days of a holiday or a contract term), and Monday to Friday becomes 5.
How are months counted?
In calendar months. 15 January to 15 March is exactly 2 months, even though February is short. When the end day is earlier in the month than the start day, the calculator counts back to the previous month and adds the leftover days, so 15 January to 4 July is 5 months and 19 days.
Does it handle leap years and time zones?
Yes. It uses real calendar dates, so 29 February is counted in leap years such as 2028. Dates are treated as whole days in your own time zone, so the answer doesn't shift by a day depending on where you are or the clocks going forward or back.
Can it count working days or business days?
Yes. Under the totals it shows working days (Monday to Friday) and weekend days. Tick 'Skip US federal holidays' to take out the eleven federal holidays on the dates they are observed: 1 November to 1 December 2026 has 21 weekdays, or 19 once Veterans Day and Thanksgiving are skipped. For another country's holidays or a company shutdown, type the dates under 'Your own days off'.
What if I work Saturdays?
Tick 'Saturday is a working day'. Working days then run Monday to Saturday, only Sundays count as days off, and adding business days steps over Sundays alone: Friday 23 October 2026 plus 1 business day becomes Saturday the 24th. Your own days off that fall on a Saturday then count too.
Can I add my own holidays?
Yes. Type them under 'Your own days off', one per line or separated by commas, as 2026-12-24 or 24/12/2026 (day first), with an optional name after the date. Each one that falls on a working day inside the range comes off the count and is listed under 'Holidays skipped'. A date typed twice, or one that's already a US holiday, counts once, and lines that aren't dates are pointed out rather than guessed at.
How do I find the date 90 days from today?
In the 'Add or Subtract Time' panel, leave the base date as today and enter 90 in Days. The same panel works backwards, takes years, months and weeks too (31 January plus 1 month is 28 February), and can count business days instead: 10 business days from Wednesday 21 October 2026 is Wednesday 4 November.
About Date Difference Calculator
The Date Difference Calculator tells you how far apart two dates are, in the units you actually need: total days for a countdown or a notice period, weeks for a pregnancy or a project plan, and years, months and days for an age, a tenancy or a length of service.
It also counts the working days in the range, with the option to skip US federal holidays on their observed dates, your own company or local holidays, or both, and to count Saturdays as working days. That's what most payment terms, notice periods and shipping estimates are written in.
A second panel goes the other way. Add or subtract years, months, weeks and days, or a number of business days, from any date to find a deadline, a delivery date, the end of a 30-day return window or the start of a notice period. Dates can be shown written out, as DD/MM/YYYY, MM/DD/YYYY or YYYY-MM-DD.
It works with plain calendar dates in your own time zone, so the result doesn't move by a day because of time zones or daylight saving. Everything runs in your browser.