Business Days Calculator
Count working days (Mon–Fri) between two dates, or add business days to a date — with optional custom holidays excluded from the count.
The counting convention
A business day here is Monday to Friday, minus any holidays you list. When counting between two
dates, the span runs from the day after the start date up to and including the end date — the
start date itself is not counted. This is the convention used for payment terms and delivery promises: "within
5 business days of Monday" means Tuesday through the following Monday, and Monday → Friday of the same week is
4 business days, not 5.
Holidays only reduce the count when they land on a weekday. A public holiday falling on a Saturday changes
nothing, because that Saturday was never counted in the first place.
Adding business days
"Add business days" steps forward one calendar day at a time and only ticks the counter on weekdays that are not
holidays. Adding 10 business days to Friday 17 July 2026 skips 2 weekends (4 weekend days) and
lands on Friday 31 July 2026 — 14 calendar days later. If 27 July were a holiday, the result
would slip to Monday 3 August.
Worked example (count mode)
From Wednesday 1 July 2026 (exclusive) to Friday 31 July 2026 (inclusive) is 30
calendar days containing 8 weekend days, so 22 business days. Add a holiday on Friday 3 July and
the count drops to 21.
Common uses
- Payment terms: net-10 or net-30 business days from an invoice date.
- Shipping and SLA promises: "ships in 3–5 business days".
- Legal and HR deadlines that exclude weekends and public holidays.
Frequently asked questions
What counts as a business day?
Monday to Friday. Saturdays and Sundays are always skipped, and any dates you list in the holidays box are skipped too — but only when they fall on a weekday, since a holiday on a Saturday would have been skipped anyway.
Is the start date included in the count?
No. Counting runs from the day after the start date up to and including the end date. So Monday to Friday of the same week is 4 business days, and "invoice date + 5 business days" means five full working days after the invoice date.
How do I add my country’s public holidays?
Type or paste them into the holidays box, one date per line in YYYY-MM-DD format (e.g. 2026-12-25). Blank lines are ignored. Each weekday holiday inside the span reduces the count by one.
What does "add business days" do with weekends?
It steps forward one calendar day at a time and only counts weekdays that are not holidays. Adding 3 business days to a Thursday lands on Tuesday (Friday, Monday, Tuesday), or Wednesday if Monday was a holiday.
Can I count business days into the past?
Enter the earlier date as the start and the later date as the end — the count between any two dates works regardless of whether they are in the past or future. The "add" mode only steps forward.