How to Count Business Days Between Two Dates

A supplier promises delivery "within 10 business days". A contract gives you a 30-working-day notice period. Neither means 10 or 30 calendar days, and knowing the difference can save you from missing a deadline.

A tidy office desk with a calendar and supplies

What counts as a business day?

Usually Monday to Friday, excluding public holidays. Saturdays and Sundays are skipped. Note that in some countries the weekend falls on different days (for example Friday and Saturday), so check the convention that applies to you.

Counting by hand

From Monday 21 September to Monday 28 September:

21, 22, 23, 24, 25 are weekdays → 5 days
26 and 27 are the weekend → skipped
If the 28th is the end date and isn't counted, the answer is 5 business days

Now suppose the 23rd is a public holiday. That leaves 4 business days.

Whether to count the start and end dates

Conventions differ, so it pays to be explicit:

Many deadline calculations count the start date but not the end date.
Others count from the day after the start.
Some contracts count both ends.

If it matters legally or financially, check the exact wording. The calculator lets you choose whether to count the end date.

Handling holidays

Public holidays vary by country, region and employer, and some move year to year. That's why the Business Days Calculator lets you list your own holidays, one per line as YYYY-MM-DD. Holidays that already fall on a weekend are ignored so nothing is double-counted.

A person marking important dates on a desk calendar

Where business days matter

Shipping and delivery estimates ("3–5 business days").
Notice periods and contract terms.
Payment terms such as "net 10 business days".
Project planning and sprint lengths.
Bank transfers, which often don't process on weekends or holidays.

Adding business days to a date

To find a date 10 business days ahead, count forward over weekdays only. A rough shortcut is that 5 business days equal 1 calendar week, so 10 business days is about 2 weeks — plus any holidays in between.

FAQ

Are Saturdays business days? Not in most calculations. Some shops and banks treat Saturday as a partial working day, but the standard definition is Monday to Friday.

Do business days include the day I start? It depends on the rule you're following. Decide up front, and use the same rule consistently.

How many business days are in a year? Roughly 260 weekdays, minus around 8–15 public holidays depending on the country.

Try it now

Open the free Business Days Calculator, add your holidays and get the count instantly.