How to Count Business Days Between Two Dates

Business days — Monday through Friday, excluding weekends — are how most deadlines, delivery windows, and payment terms are actually measured. Counting them by hand is fiddly, so here's the method, plus the one thing every online calculator (including ours) can't do for you.

What counts as a business day

A business day, also called a working day, is any weekday: Monday, Tuesday, Wednesday, Thursday, or Friday. Saturdays and Sundays don't count. So a delivery promised in "3 business days" and ordered on a Thursday would arrive the following Tuesday, not Sunday — because the weekend is skipped.

Counting them manually

For a short span, count on your fingers, skipping weekends. For a longer span, there's a quick trick: take the total number of days and note how many full weeks it contains. Each full week has exactly five business days. Then add the leftover weekdays from the partial week at the end. For example, 30 calendar days is 4 full weeks (20 business days) plus 2 leftover days — so somewhere between 20 and 22 business days depending on which weekday you start.

The holiday problem

Here's the catch no automatic calculator can solve universally: public holidays. A "business day" in practice also excludes bank and national holidays — but those differ by country, and even by state or region within a country. A US federal holiday means nothing in the UK, and vice versa. Because of that, our Date Difference Calculator counts weekdays only and deliberately does not subtract holidays. If your deadline falls near one, subtract those days yourself.

Why it matters

Payment terms like "net 30" sometimes mean 30 calendar days and sometimes 30 business days — a difference of nearly two weeks. Contracts, notice periods, and shipping estimates all hinge on which convention is used. When a deadline matters, confirm whether it's calendar days or business days before you count.

Let the tool count

Rather than counting by hand, drop your two dates into the Date Difference Calculator. It reports the total days, weeks, months, and the number of business days in the span — then you just adjust for any holidays that apply where you are.