Quick answer
Business days are the dates that count as working days under the rules you choose. A common calculation counts Monday through Friday, excludes applicable holidays, and specifies whether the start and end dates are included.
The rules can vary by jurisdiction, employer, industry, contract, or calculator settings.
What counts as a business day?
A calendar day is any date, including weekends and holidays. A business day is a date eligible under a particular working calendar. Many office schedules use Monday through Friday, so Saturday and Sunday are excluded as regular nonworking days.
That pattern is common, not universal. A service can operate on Saturday without Saturday counting toward its quoted processing time. A shift worker’s roster may also differ from the calendar used for a payment or deadline. First identify whose rules you need.
Common misunderstanding
- “Five business days always means one calendar week.” Holidays, cutoff times, and the day counting starts can change the finish date.
- “Every business uses the same holidays and weekends.” Country, regional, employer, and service rules can differ. A calculator follows its settings, not every possible definition.
Simple examples: count both endpoints
Assume a Monday–Friday working week and include both the start date and the end date. The first two examples have no holidays. The third adds one hypothetical weekday closure.
Monday → Friday
5 business days
Monday, Tuesday, Wednesday, Thursday, and Friday all count.
Monday → next Monday
6 business days
Count the first five weekdays and the following Monday; skip Saturday and Sunday.
One weekday holiday
5 business days
In that Monday-to-next-Monday range, exclude Wednesday if it is a holiday or closure under your rules.
How including or excluding an endpoint changes the result
| Start date | End date | Business days |
|---|---|---|
| Included | Included | 6 |
| Excluded | Included | 5 |
| Included | Excluded | 5 |
| Excluded | Excluded | 4 |
The start of a date range is not necessarily “day one” of a deadline. If a policy starts counting on the next business day, follow that rule. Including an endpoint adds a business day only when that date qualifies; a weekend or excluded holiday still does not count.
Why holidays and local rules change the total
Count each eligible date once. Remove a holiday only if it would otherwise have been a working day in the chosen range.
Country and region
Public holidays can differ within a country. The UK, for example, publishes separate lists for England and Wales, Scotland, and Northern Ireland.
Observed holidays
A holiday on a weekend may have a substitute weekday. Check the applicable observed date rather than assuming the weekend date is the only exclusion.
Working-week rules
Some schedules use different nonworking days. A Monday–Friday total will not describe every workplace or industry.
Custom closures
A company shutdown or other agreed nonworking date can reduce the count. Add only closures relevant to the schedule you are measuring.
Avoid subtracting the same date twice
If a holiday falls on an already excluded Saturday, that Saturday does not reduce the total again. If an observed Monday is also excluded, Monday is a separate nonworking date. Likewise, one date appearing in both a public-holiday list and your custom list should count as just one exclusion.
For example, US federal holiday guidance has specific substitute-day rules for federal employees, including different schedules. Those rules are not a universal calendar for private employers or other countries. Check Holidays in Calendar and the rules for the organization involved.
How to use business-day counts
Before calculating, confirm the date range, working week, holiday list, endpoint rules, and any time-of-day cutoff.
Deadlines and contracts
Read the relevant definition of “business day,” when counting starts, and the due time. A simple date total does not decide a contract’s deadline rules.
Shipping and processing
Check the carrier or seller’s calendar and order cutoff. Processing days, transit days, and delivery days may follow different schedules.
Payroll and staffing
Use the employer’s payroll calendar and each applicable work schedule. A business-day count alone does not calculate payable hours, overtime, or pay.
Projects and planning
Estimate available working dates and allow for planned closures. Record your assumptions so colleagues can reproduce the result.
Use the SkyAndTime Business Days calculator
Open the Business Days calculator from Calculators. It excludes Saturdays and Sundays. The start date is considered; the Include the end date checkbox controls whether the end date is considered too.
Load country holidays for the relevant year and select the dates to exclude. For a range crossing years, load and select the applicable dates for each year. Enable country holidays, custom holidays, or both as needed. Check regional and observed dates, and add any missing applicable closure as a custom date.
To reproduce the examples above, include the end date and begin with no selected holidays. Adding the Wednesday closure reduces the six-day example to five. Overlapping holiday entries count once. The tool currently uses a fixed Saturday–Sunday weekend; a different working week needs a separate calculation or review.
Frequently asked questions
Does Monday to Friday count as five business days?
Yes, if both Monday and Friday are included, the working week is Monday to Friday, and no date is an excluded holiday. Excluding either endpoint changes that example to four.
Are Saturdays and Sundays always excluded?
No universal rule applies. Many office calendars exclude both, but working schedules and service definitions vary. SkyAndTime’s Business Days calculator currently excludes Saturday and Sunday.
Do public holidays automatically reduce the count?
Only dates excluded by the applicable rules reduce the count. A holiday on an already excluded weekend is not subtracted twice; a separate observed weekday may need to be excluded. In SkyAndTime, select the relevant holidays and enable their use.
Can I exclude company closures as well as public holidays?
Yes. Add relevant custom dates and enable custom holidays. SkyAndTime combines enabled country and custom dates, counting an overlapping date once.
Is the start date included in SkyAndTime’s calculation?
The start date is considered and counts if it is a weekday that is not excluded as a holiday. The end date is considered only when Include the end date is checked. For a deadline that starts later, choose the starting date required by that rule.
Sources & further reading
References checked September 27, 2026. Worked examples state their counting assumptions; applicable rules can differ.
