How to Calculate Business Days Between Two Dates

Your vendor says the refund will land in five business days. You count forward on the calendar, assuming every day counts, and by day five — a Saturday — you're annoyed it hasn't shown up. It was never going to. Five business days from a Tuesday lands the following Tuesday, not the following Sunday, because weekends don't count toward the total.

This guide covers the exact method for counting business days between two dates, a faster shortcut once the logic clicks, how public holidays change the count, and the spreadsheet formula that does it instantly. If you just need one answer right now, the business days calculator does the counting for you; if you want the method itself, so you can do it by hand or sanity-check a spreadsheet, keep reading.

A business day is any day that falls Monday through Friday. Saturdays and Sundays are excluded by definition — no exceptions, no judgment calls. That's the baseline every business-day calculation starts from.

How far the definition extends depends on who's asking. A shipping estimate usually means exactly that: Monday to Friday, full stop. A contract, a court filing deadline, or an HR policy usually means something narrower — Monday to Friday minus public holidays, because an office that's closed for a holiday can't process anything that day either. When "business day" appears in something binding, like a lease or a legal notice, assume the holiday exclusion applies until you've confirmed otherwise.

The reliable way to count business days between two dates doesn't need a formula — it needs patience. Write out every calendar date from the start to the end, cross out anything that lands on a Saturday or Sunday, and count what's left.

It's slower than the shortcut in a later section, but it's the method that never gets tricked by an odd date range, and it's worth doing by hand at least once so you trust the faster version.

This is where most counting errors happen, and it comes down to wording, not arithmetic. A deadline phrased "by Friday, September 18" almost always counts both the day you start and the day you finish — the inclusive count used above, and the default a spreadsheet's NETWORKDAYS-style formula gives you.

A deadline phrased "5 business days from today" usually means the count starts the day after the start date, not on it. Same starting date, same number — ten — but two different questions get asked. "How many business days are there between September 7 and September 18?" (inclusive of both ends) gives ten, as shown above. "What date is ten business days from September 7?" (excluding the start) gives Monday, September 21 instead, because the count doesn't begin until the next day: Tue 8, Wed 9, Thu 10, Fri 11, Mon 14, Tue 15, Wed 16, Thu 17, Fri 18, Mon 21.

Read whatever deadline you're working from carefully, and if it doesn't specify, ask rather than assume.

Once you trust the manual count, there's a shortcut that skips writing out every date.

Pick a start and end date and this counts the business days between them — Monday through Friday only, both dates inclusive. It doesn't know your local holiday calendar (see the next section for why), so treat the result as weekend-adjusted only.

Weekends are consistent within a given working week — the same two days off, week after week. Public holidays are not: the list is different in every country, and often different from one company, state, or industry to the next. There's no way to bake a universal holiday list into a business-day calculation, so it has to be handled as its own step.

The method: count the weekday-only total first, using the manual method or the shortcut above, then subtract one day for every public holiday that falls on a weekday inside your date range. If a holiday lands inside the 12-day range from the earlier example, the count drops from ten business days to nine.

Both Excel and Google Sheets have a function built for exactly this: NETWORKDAYS. Give it a start date and an end date and it returns the number of weekdays between them, inclusive of both ends — the same inclusive count used in the manual method above.

The basic formula is =NETWORKDAYS(start_date, end_date). To exclude public holidays too, add a third argument pointing at a range of holiday dates: =NETWORKDAYS(start_date, end_date, holiday_range). If your business week doesn't run Monday to Friday — a Friday–Saturday weekend, for instance — both platforms also offer NETWORKDAYS.INTL, which takes a weekend-pattern code instead of assuming Saturday and Sunday.

Going the other direction — finding a date that's a certain number of business days from a start date — the matching function is WORKDAY (or WORKDAY.INTL for a custom weekend). It's the formula version of the "10 business days from Monday" question from earlier in this guide.

"Ships in 3–5 business days" on an online order means the warehouse is estimating processing and carrier pickup time, skipping the days it isn't open. Order Thursday evening and the clock effectively doesn't start until Friday or Monday, depending on the cutoff time.

Legal and contractual deadlines — "respond within 10 business days," "the tenant has 5 business days to cure the default" — are the cases where the inclusive-vs-exclusive question from earlier has real money or legal standing attached to it. Read the exact wording, and when it's ambiguous, get the other party to confirm it in writing rather than assuming.

Payroll processing runs on its own business-day cutoffs, usually layered on top of hours already worked. If you're trying to work out overtime pay rather than a calendar deadline, see how to calculate overtime hours and pay instead.

Loan closings, mortgage rescission periods, and standard trade-settlement timelines ("T+2 business days") in finance all use the same weekday-only counting logic covered here.

• Treating "business days" as "calendar days" and forgetting to skip weekends at all — the single most common error.
• Getting the inclusive/exclusive boundary wrong and landing a day off in either direction.
• Ignoring public holidays when the deadline is contractual or legal and the wording implies they're excluded.
• Assuming a Saturday–Sunday weekend for an international deadline without checking the local working week.
• Confusing "business days" with a company's non-standard schedule — some run compressed four-day weeks, which changes internal deadlines even though the Monday–Friday definition itself doesn't.