How to Calculate Business Days Between Dates

Delivery windows, notice periods, and payment terms are often quoted in business days rather than calendar days, so knowing how to count business days between dates saves confusion and missed deadlines. Business days are simply the working days of the week, and counting them means excluding weekends and public holidays from your total. This guide explains exactly what counts as a business day, shows how to calculate them by hand, gives a quick estimate for longer spans, and covers the common real-world uses. Because manual counting is fiddly once holidays are involved, our date difference calculator can do it for you, but the method below helps you understand and check the result.

What are business days?

A business day, also called a working day, is any day when businesses and banks are normally open. In most countries that means Monday to Friday, excluding Saturday, Sunday, and public holidays. So a deadline of five business days does not mean five calendar days; it skips over any weekends and holidays that fall in between.

Weekends and which days are public holidays vary by country and even region, so always use the calendar that applies to your situation.

How to count them

1. Count the total number of days in your date range.
2. Subtract every Saturday and Sunday that falls within it.
3. Subtract any public holidays that land on a weekday.

The result is the number of working days. The trickiest part is remembering the holidays, which is exactly where a calculator helps.

A worked example

Suppose you start counting from a Monday and want to know when 10 business days have passed, with no public holidays in between.

1. 10 business days is two working weeks.
2. Two working weeks span two weekends, which is 4 non-working days.
3. So 10 business days later is 10 + 4 = 14 calendar days later.

In plain English: ten business days from a Monday lands on the Friday two weeks later, because two weekends (four days) fall in the gap. If a public holiday also occurred, you would extend the end date by one more day.

Count any range instantly

Our date difference calculator counts the days between any two dates, and our guide on calculating days between two dates covers the calendar-day version in detail.

A quick estimate

For a fast approximation over a longer period, use the fact that five of every seven days are business days.

So 30 calendar days is roughly 30 x 5 / 7, about 21 business days, before subtracting any public holidays. This estimate is close for whole weeks but should be checked exactly when a deadline really matters.

Where business days are used

• Deliveries and shipping: estimated arrival is often given in business days.
• Payment terms: invoices may be due within a set number of business days.
• Notice periods: employment and legal notices are sometimes counted in working days.
• Bank transfers: clearing times are usually quoted in business days.

Frequently asked questions

How do I calculate business days between two dates?

Count the total number of days in the range, then subtract every Saturday and Sunday, and any public holidays that fall on a weekday. The result is the number of business days. For example, a 14-calendar-day span with no holidays contains 10 business days, because two weekends remove four days.

What counts as a business day?

A business day is a working day when businesses and banks are typically open, usually Monday to Friday. It excludes weekends, normally Saturday and Sunday, and public holidays. The exact weekend days and holiday dates vary by country and region, so use the calendar that applies to your location when counting.

How many business days are in a week?

There are normally five business days in a week, Monday through Friday, with Saturday and Sunday as the weekend in most countries. Some regions observe a different weekend, so the working days can differ. Public holidays that fall on a weekday reduce the number of business days in that particular week.

How do I estimate business days quickly?

Multiply the number of calendar days by 5 and divide by 7, since five of every seven days are working days. For 30 calendar days, that is about 21 business days. This is an approximation that works well for whole weeks; subtract any public holidays and verify exactly when a precise deadline matters.

Do business days include holidays?

No. Public holidays are excluded from business days, even though they may fall on a weekday, because businesses and banks are typically closed. When counting business days, subtract both weekend days and any public holidays in the range. Since holidays vary by country and region, always check the relevant calendar.

The bottom line

Business days are the working days of the week, Monday to Friday, excluding weekends and public holidays. To count them, take the total days and subtract the weekends and any weekday holidays, so 10 business days from a Monday is 14 calendar days later. For a quick estimate, multiply calendar days by 5/7. When accuracy matters, let our date difference calculator do the counting.

Further reading

For authoritative background on this topic, see Business day on Wikipedia.