📅 Date & Time
How to Add Business Days to a Date (Skipping Weekends)
Deadlines are often set in working days, not calendar days. Learn how to add or subtract business days from a date, why weekends are skipped, and how holidays fit in.
Updated 2 November 2026 · 2 min read
Plenty of deadlines are written in working days rather than calendar days — "delivery within 5 business days", "you have 10 working days to respond", "funds clear in 3 business days". Counting these by hand is fiddly because you have to jump over every weekend, and it's easy to be a day or two out.
What counts as a business day
A business day (or working day) is normally Monday to Friday. Saturdays and Sundays are skipped, because most offices, banks and couriers don't operate then. So adding business days means stepping forward one weekday at a time and simply not counting the weekend days you pass over.
How to count by hand
- Start the day after your start date (the start date itself usually isn't counted).
- Move forward one day at a time.
- Tick off a day only if it's a Monday to Friday; skip Saturdays and Sundays without counting them.
- Stop when your tally reaches the number of business days you need.
For example, 3 business days after a Thursday: Friday (1), skip the weekend, Monday (2), Tuesday (3) — so you land on Tuesday. Subtracting works the same way in reverse. The add working days calculator does this instantly in either direction, which saves counting on your fingers for longer stretches.
What about public holidays?
Strictly, a business day also excludes public holidays — but which days those are depends entirely on the country, and often the region. A bank holiday in the UK isn't one in the US, and vice versa. Because of that, a general-purpose tool skips weekends but leaves holidays to you: if a national holiday falls inside your window, add one more day for each one to get the true business date.
Business days vs calendar days
- Calendar days count every day, weekends included — used for most legal notice periods and subscriptions.
- Business days count only weekdays — used for shipping, bank transfers and many response deadlines.
- The gap adds up fast: 10 business days is two full weeks, which is 14 calendar days.
If you instead need the plain number of days between two dates, or to add ordinary calendar days, see our guides on adding days to a date and counting working days between two dates, which covers the reverse problem of measuring a span rather than projecting one forward.
Frequently asked questions
- Does the start date count as day one?
- Usually no — counting normally begins the next working day, so '3 business days from Monday' lands on Thursday. Conventions vary by contract, though, so check the exact wording where a deadline really matters.
- Are public holidays skipped too?
- In principle yes, but holidays differ by country and region, so a general tool skips only weekends. If a public holiday falls within your window, add an extra day for each one.
- How many calendar days is 10 business days?
- Assuming no public holidays, 10 business days spans two working weeks, which is 14 calendar days from the start of the first week — because two weekends fall inside that stretch.