About this calculator
Find out how many days there are between two dates, or what the date will be after you add or subtract a number of days. The result also shows weeks, months and the number of working days.
You can count calendar days or working days (Monday to Friday), and choose whether to count the last day. Leap years are handled for you.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
1 January to 31 December 2026
- Days
- 364 days
- Weeks and days
- 52 weeks
- Years, months and days
- 11 months, 30 days
- Working days (Mon to Fri)
- 260 days
From Thursday 1 January 2026 to Thursday 31 December 2026 is 364 days, of which 260 days are weekdays. Public holidays aren't taken off.
28 September to 5 October 2026, counting both days
- Days
- 8 days
- Weeks and days
- 1 week, 1 day
- Years, months and days
- 8 days
- Working days (Mon to Fri)
- 6 days
From Monday 28 September 2026 to Monday 5 October 2026 (counting both days) is 8 days, of which 6 days are weekdays. Public holidays aren't taken off.
30 days after 29 September 2026
- Resulting date
- Thursday 29 October 2026
Adding 30 days to Tuesday 29 September 2026 gives Thursday 29 October 2026.
10 working days after 2 October 2026
- Resulting date
- Friday 16 October 2026
Adding 10 working days to Friday 2 October 2026 gives Friday 16 October 2026. Weekends are skipped; public holidays are not.
How days between dates are counted
The number of days between two dates is the later date minus the earlier one. From 28 September to 5 October is 7 days, because you count the nights, not the calendar squares.
If you want to count both the first and last day (for example, a booking that covers both), choose “Count both the first and last day” and you'll get 8 days. Which one is right depends on how your contract, deadline or notice period is worded, so check the wording.
Working days
Working days here are Monday to Friday. Public holidays are not removed, because they differ by country and year. For UK bank holidays, check GOV.UK's bank holiday list and subtract any that fall in your range.
Leap years and months
Leap years are counted correctly: 28 February to 1 March is 2 days in 2024 but only 1 day in 2025. The “years, months and days” line adds whole calendar months first. If the start day doesn't exist in a month (31 January plus one month), it uses the last day of that month, so 31 January to 1 March is 1 month and 1 day.
Frequently asked questions
How many days are there between two dates?
Subtract the earlier date from the later one. Choose “count both the first and last day” if your dates are inclusive, which adds one.
How do I add 30 days to a date?
Enter the date, choose “Add”, type 30 and choose calendar days. The calculator shows the date and the day of the week.
How do I count working days?
Choose working days when adding days, or read the working days line when counting between dates. Both skip Saturdays and Sundays.
Does it remove bank holidays?
No. Public holidays vary by country and year, so subtract those yourself. GOV.UK publishes the UK list.
Does it handle leap years?
Yes. 29 February is counted in leap years such as 2024 and 2028, and skipped in other years.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.