Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Working days
0
Working hours
0.0
Weekdays before holidays
0
Weekend days
0
Calendar days
0
Working weeks
0.00
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter start date.
- 2Enter end date.
- 3Enter holidays in the range.
- 4Enter working hours per day.
- 5Read your working days on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Contract turnaround, SLA windows, and payroll cutoffs all run on business days. Subtract your company holidays to get the number teams actually plan against.
Worked example
Using the values the calculator loads with:
Inputs
- Start date: 2026-08-15
- End date: 2026-08-15
- Holidays in the range: 0
- Working hours per day: 8
Results
- Working days: 0
- Working hours: 0
- Weekdays before holidays: 0
- Weekend days: 0
- Calendar days: 0
- Working weeks: 0
What each field means
Inputs
- Start date
- The reference date for this calculation. Defaults to today unless you change it.
- End date
- The reference date for this calculation. Defaults to today unless you change it.
- Holidays in the range
- The holidays in the range used in the calculation. Starts at 0 so you have a working example on load. Accepted range: 0–40.
- Working hours per day
- The working hours per day used in the calculation. Starts at 8 so you have a working example on load. Accepted range: 1–24.
Results
- Working days
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Working hours
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Weekdays before holidays
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Weekend days
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Calendar days
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Working weeks
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the business days calculator work?
Contract turnaround, SLA windows, and payroll cutoffs all run on business days. Subtract your company holidays to get the number teams actually plan against. The underlying maths is: Business days = Total days − weekends − holidays.
What do I need to enter?
4 values: start date, end date, holidays in the range, and working hours per day. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the working days result mean?
It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Business Days Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/business-days
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/business-days" target="_blank" rel="noopener">Business Days Calculator — RevenueLab</a> (2026).</p>
Source: [Business Days Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/business-days) (2026).