How to Count Business Days Between Two Dates

By HSP · Published October 5, 2026 · 5 min read · Math & Dates

Deadlines, delivery estimates, notice periods, invoice terms and project plans are often written in business days rather than calendar days. “Payment within 10 business days” or “5 to 7 working days for delivery” can mean very different calendar dates depending on weekends and holidays. Here is how to count them correctly, plus the spreadsheet formulas that do it for you.

What counts as a business day?

In most countries, a business day is Monday to Friday, excluding public holidays. Some industries and countries use a different working week; for example, in several Middle Eastern countries the weekend falls on Friday and Saturday or on Saturday and Sunday. Banks also follow their own holiday calendars. Always check which days the contract, employer or service provider counts.

Step 1: Decide whether the end dates are included

This is where most disagreements come from. If a task starts on Monday and finishes on Friday of the same week, is that 5 business days or 4? Counting both days (inclusive) gives 5; counting the gap between them gives 4. Contracts often say “within 10 business days of receipt”, which usually means you start counting the day after receipt. When in doubt, ask or state your assumption in writing.

Step 2: Count the weekdays

For short ranges, look at a calendar and count Monday to Friday. For longer ranges, use full weeks:

1. Count the number of full weeks in the range and multiply by 5.
2. Add the weekdays in the leftover partial week.

Example: Monday 5 October 2026 to Friday 30 October 2026, counting both days. That is exactly four full weeks (Monday to Friday each week), so 4 × 5 = 20 business days. The calendar-day difference between the two dates is 25 days.

Step 3: Subtract public holidays

Take away any public holidays that fall on a weekday inside your range. Holidays on weekends are already excluded, although some countries move them to the following Monday (“observed” holidays), so check your official list.

In the example above, Monday 12 October 2026 is Thanksgiving in Canada and Columbus Day (also observed as Indigenous Peoples’ Day in many places) in the United States. If your organisation closes that day, the count drops to 19 business days. The U.S. Office of Personnel Management publishes the federal holiday calendar each year; other countries publish similar lists.

Using our calculator

The date difference calculator shows calendar days and business days (Monday to Friday) between any two dates. Tick “include end date” if both the first and last day should count. It does not know your local holidays, so subtract any that fall on weekdays in your range. It also shows the difference in weeks, months and years, which is handy for notice periods and project timelines.

Counting business days in Excel and Google Sheets

NETWORKDAYS

=NETWORKDAYS(start_date, end_date, [holidays]) returns the number of working days between two dates, counting both the start and end dates and excluding weekends. Put a list of holiday dates in a range, for example H2:H12, and pass it as the third argument: =NETWORKDAYS(A2, B2, H2:H12). With A2 = 5 Oct 2026, B2 = 30 Oct 2026 and 12 Oct 2026 in the holiday list, the result is 19.

NETWORKDAYS.INTL for other weekends

If your weekend is not Saturday and Sunday, use NETWORKDAYS.INTL, which takes a weekend code. For example, weekend code 7 means Friday and Saturday. You can also pass a seven-character string such as "0000011", where each digit represents Monday to Sunday and 1 marks a non-working day.

WORKDAY: finding a deadline

To go the other way, finding the date that is a given number of business days after a start date, use =WORKDAY(start_date, days, [holidays]). For example, 10 business days after Monday 5 October 2026, with 12 October as a holiday, is Tuesday 20 October 2026. WORKDAY does not count the start date itself.

Example: a delivery estimate over the holidays

A shop says orders take 15 business days. You order on Monday 21 December 2026. Counting from 21 December to Friday 8 January 2027 inclusive there are 15 weekdays, but Friday 25 December and Friday 1 January are public holidays in many countries, and Boxing Day falls on a Saturday in 2026 so some places observe it on Monday 28 December. Your delivery could easily move into the week of 11 January or later. When a range crosses major holidays, always subtract them.

Business days and pay

Business days also matter for pay calculations. A full-time year has roughly 260 weekdays (52 weeks × 5), and the U.S. Office of Personnel Management uses 2,087 hours as the standard work year for converting annual salaries into hourly rates. If you are comparing hourly and salaried jobs, see how to convert hourly wage to salary.

Common mistakes

• Not agreeing whether the start and end dates count.
• Forgetting holidays, especially ones that are observed on a Monday when the actual date falls on a weekend.
• Using another country’s holiday calendar when working with international teams or suppliers.
• Assuming every business uses a Monday to Friday week.

For counting calendar days, adding days to a date and other date maths, see date calculations explained. To track a deadline once you know it, set a countdown timer, and to work out someone’s age on a given date use the age calculator.