Business Day Calculator
This calculator counts how many business days fall inside a date range you enter. A business day here means Monday through Friday: the tool skips Saturday and Sunday, then subtracts the number of public holidays you enter so you can adjust for days off that fall on a weekday. The result is useful for delivery estimates, contract notice periods, payroll cut-offs, sprint planning, and any deadline that counts working days instead of calendar days. This page does not look up official holiday calendars for any country, does not schedule events, and does not send reminders.
Method and formula
The calculator walks through every calendar day from the start date to the end date, counting days whose weekday is Monday through Friday:
business days = count of dates in [start date … end date] whose weekday is Mon–Fri
Both endpoints are included. The other outputs follow directly:
total days = (end date − start date) + 1
weekend days = total days − business days
adjusted business days = max(0, business days − holidays)
Enter the holidays value as the count of public holidays that fall on a Monday–Friday inside your range. If your range runs backwards, the tool counts the same span from the later date to the earlier date, so the result stays positive.
Worked example
For a range from Tuesday, 2026-09-01 to Wednesday, 2026-09-30 with 1 holiday in the period:
- Total days: 30
- Weekend days: 8 (four Saturdays and four Sundays)
- Business days: 30 − 8 = 22
- Adjusted business days: 22 − 1 = 21
As a second example, a range from Friday, 2026-03-06 to Monday, 2026-03-09 contains four calendar days, of which two (Friday and Monday) are business days.
What the result means
"Business days" is the raw Monday–Friday count inside the range, including both endpoint days when they fall on a weekday. "Adjusted business days" subtracts the holiday count you entered and never goes below zero. The results describe the calendar only: they do not predict how long a task will take, and they do not decide which specific dates are holidays.
Business-day conventions differ between organisations. Some employers count Saturday as a working day, some regions use Friday–Saturday weekends, and holiday schedules are country-specific. If your rules differ, treat the adjusted result as a starting point and correct it manually.
Accuracy and limitations
- Dates must be valid Gregorian calendar dates. The calculator uses your device's local time zone for date parsing and counts whole days only; hours and minutes are ignored.
- The tool does not ship a holiday database. The holidays input is a plain count, so it cannot skip specific named holidays on specific dates for you.
- Weekend definitions are fixed to Saturday and Sunday in this version. Five-day weeks running Tuesday–Saturday or Sunday–Thursday are not modelled.
- Contract law, labour law, and service-level agreements often define business days and notice periods precisely. For legal or compliance deadlines, confirm the counting convention with the applicable rules before relying on the result.
Sources
- ISO 8601 — Date and time format — the Gregorian calendar and weekday conventions the tool assumes.
- NIST Special Publication 811, Guide for the Use of the International System of Units — guidance on expressing counts and quantities used in the outputs.
Editorial record
- Author: SoupCalc Editorial Team
- Method review: SoupCalc Engineering Review
- Last reviewed: September 2, 2026
- Review scope: weekday-counting logic, holiday adjustment, examples, source links, and claims about the tool's actual functions