Date calculator

How the date calculator works

The top part counts the number of days from your start date to your end date. By default it doesn't count the end date itself, so from Monday to Friday of the same week is 4 days. That's how most people count "how many days until" something, and how nights in a hotel are counted. Tick "include the end date" to count both days, which gives 5 days for Monday to Friday and is usually what you want for working days, leave or a notice period.

Working days are Monday to Friday. With the bank holidays box ticked, England and Wales bank holidays are taken off too. The bottom part adds or subtracts days, weeks, months, years or working days to give you a new date.

England and Wales bank holidays 2026 and 2027

These are the dates the calculator leaves out of working days, taken from GOV.UK. Scotland and Northern Ireland have some different bank holidays, such as St Andrew's Day and St Patrick's Day, so check your own if you work there.

When Christmas Day or Boxing Day falls at a weekend, the bank holiday moves to the next weekday, called a substitute day. That's why in 2027, with Christmas on a Saturday, the bank holidays are on Monday 27 and Tuesday 28 December.

Worked examples

How many days until Christmas?

From 1 January 2026 to 25 December 2026 is 358 days (51 weeks and 1 day), not counting Christmas Day itself. Of those, 256 are weekdays, and 250 are working days once you take off the six bank holidays that fall before 25 December.

Working days over Christmas

From Monday 21 December 2026 to Monday 4 January 2027, including both dates, is 15 days. There are 11 weekdays, but three of them (25 December, 28 December and 1 January) are bank holidays, leaving 8 working days.

Adding working days

Ten working days after Friday 23 October 2026 is Friday 6 November 2026, skipping two weekends. Adding 3 months to 30 November 2026 gives 28 February 2027, because February has no 30th; the calculator uses the last day of the month in that case.

When you might need it

• Notice periods and deadlines: many contracts, refunds and legal deadlines are set in days or working days, such as 14 days to cancel an online order.
• Annual leave: count how many working days a holiday will use. Our holiday entitlement calculator works out how many days you're entitled to.
• Countdowns: days until a wedding, holiday, exam or due date.
• Payment terms: invoice "net 30" terms usually mean 30 calendar days, not working days, so check which your contract says.

Tips

• Dates are counted in whole days and aren't affected by the clocks changing for British Summer Time.
• If your workplace closes for extra days, such as between Christmas and New Year, take those off the working days figure yourself.
• For someone's exact age in years, months and days, use the age calculator. To add up hours worked rather than days, try the hours calculator.

Last reviewed October 2026 using 2026/27 figures. This calculator gives an estimate for guidance only.