How the days between two dates are counted
By default the calculator counts the number of days from the start date up to, but not including, the end date. This is the same as counting the number of midnights in between, and it is how most people measure an interval: from Monday to the next Monday is 7 days.
If you choose to include the end date, one day is added. Use this when both the first and last day count, for example a holiday from 1 to 7 August (7 days of holiday, not 6) or an event that runs over several days.
Years, months, weeks and weekdays
- Years, months and days: the calculator counts whole calendar years first, then whole months, then the remaining days. Because months have 28 to 31 days, this is a calendar difference rather than a fixed number of days.
- Weeks: total days ÷ 7, shown as whole weeks plus the remaining days.
- Weekdays: every Monday to Friday in the range is counted (start date included, end date excluded unless you include it).
- Weekend days: total days − weekdays.
- Hours: total days × 24. Clock changes for British Summer Time are ignored.
Worked example 1: days until Christmas
From Thursday 15 October 2026 to Friday 25 December 2026
Remaining days in October (16 to 31) = 16, plus 15 October itself = 17
November = 30 days; December up to the 24th = 24 days
Total = 17 + 30 + 24 = 71 days
That is 2 months and 10 days, or 10 weeks and 1 day
Weekdays = 51, weekend days = 20, hours = 1,704
Worked example 2: a whole year including the end date
From 1 January 2026 to 31 December 2026, end date included
2026 is not a leap year, so the result is 365 days (1 year, 0 months, 0 days)
That is 52 weeks and 1 day
Weekdays = 261, weekend days = 104
England and Wales have 8 bank holidays in 2026, so there are 261 − 8 = 253 working days
Worked example 3: a longer period
From 10 February 2024 to 15 October 2026
Total = 978 days, which includes 29 February 2024
Calendar difference = 2 years, 8 months and 5 days
= 139 weeks and 5 days; 698 weekdays and 280 weekend days
Worked example 4: a four-week notice period
Notice given on Monday 2 March 2026, ending Monday 30 March 2026
Days between = 28 (exactly 4 weeks)
Weekdays = 20, so 20 working days if there are no bank holidays in between
Check your contract: some notice periods count the day notice is given, others start the next day.
UK bank holidays to remember
The calculator does not remove bank holidays because they differ across the UK. Deduct them yourself for working-day counts:
- Extra one-off bank holidays are sometimes announced for national events.
- When a bank holiday falls at the weekend, a 'substitute' weekday is usually given instead.
| Nation | Bank holidays per year (usual) |
|---|---|
| England and Wales | 8 |
| Scotland | 9 |
| Northern Ireland | 10 |
Common mistakes when counting days
- Counting both ends by accident. Counting on your fingers from the 1st to the 10th gives 10, but only 9 days have passed. Decide whether the end date should be included.
- Assuming every month has 30 days. Use the actual calendar, especially across February.
- Forgetting leap years. 2028 is the next leap year, with 29 February.
- Treating weekdays as working days. Bank holidays, shift patterns and part-time hours all reduce working days.
- Legal and contractual deadlines may follow specific rules (for example 'clear days' or business days); check the wording.