How to use this calculator
- Choose what you want to do. Count the working days between two dates (for example, to check how long a project really has), or add working days to a date (for example, "payment due within 10 working days").
- Choose the public holidays to skip. The UK has three sets of bank holidays. The US option uses federal holidays, which many businesses follow but some don't.
- Pick your dates. When counting, choose whether the start date itself counts.
How it's calculated
Working day = Monday to Friday, and not a public holiday in the region you chose
Counting = the working days from the start date to the end date
(the end date always counts; the start date if you tick the box)
Adding = step forward one day at a time from the start date (which isn't counted),
skipping weekends and public holidays, until enough working days have passed
Worked examples
1 to 31 October 2026, England and Wales = 22 working days
1 to 31 October 2026, United States = 21 working days (Columbus Day, 12 October)
10 working days after Friday 18 December 2026:
England and Wales → Wednesday 6 January 2027
(skips Christmas Day, Boxing Day on 28 December and New Year's Day)
Scotland → Thursday 7 January 2027 (also skips 4 January)
United States → Tuesday 5 January 2027
Holidays included
- UK bank holidays for England and Wales, Scotland and Northern Ireland, from 2026 to the end of 2028, from GOV.UK's official list.
- US federal holidays for 2026 and 2027 as observed by federal offices, from the US Office of Personnel Management. State holidays aren't included.
- Outside those years, only weekends are skipped, and the result tells you.
Frequently asked questions
What's the difference between business days and working days?
Usually nothing: both mean Monday to Friday, not counting public holidays. Some contracts define them differently, so check the wording in yours.
Why is Boxing Day on 28 December 2026?
In 2026, 26 December is a Saturday, so the bank holiday moves to the next weekday, Monday 28 December. These moved days are called substitute days.
Can I use this for invoice payment terms?
Yes. Choose "Add working days to a date", enter your invoice date and the number of days. If a UK business client pays late, our late payment interest calculator shows what you can claim.
Sources: GOV.UK: UK bank holidays; US Office of Personnel Management: federal holidays. Checked 30 September 2026.