Working Hours + Business Days Combo
Business days between two dates, converted to working hours at your own day length.
Written and maintained by Paul Clark, Redmoon Software · Rules last verified
These calculators are for informational purposes only and do not constitute legal, financial, or professional advice.
How the Working Hours + Business Days Combo works
The Working Hours + Business Days Combo answers a question that comes up whenever a commitment is written in hours but a calendar is measured in days: how many working hours does this span actually contain? It counts the business days between two dates — weekends out by your work-week pattern, public holidays out by country, custom closures out — and multiplies by the length of your own working day to give both figures at once.
The reason to anchor the hours to a business-day count rather than to a wall-clock span is that the two answer different questions and only one of them is plannable. An SLA written as "40 working hours" is not two calendar weeks; it is however long five working days take to elapse on your calendar, which over a public holiday is seven calendar days and over a Christmas period can be more. By deriving hours from days, the figure stays tied to real capacity. The hours-per-day input is what makes it yours: a 7.5-hour day with an unpaid lunch, a 6-hour part-time pattern, or a 12-hour shift all produce different totals from the same date range, and none of them is the 8 that a generic calculator would assume.
The important limit is that this tool is date-based, not timestamp-based. It does not know what time of day the span started or ended, so it treats every business day in the range as a whole working day. That is the right model for capacity planning, effort estimation and converting a day-based commitment into an hours-based one. If you need the precise elapsed working time between two moments — a ticket opened at 16:40 on Tuesday and closed at 09:15 on Thursday — that is a genuinely different calculation, and the Business Hours Between Two Dates calculator handles it with real timestamps and a lunch deduction.
Worked example
A task runs from Monday, 1 June 2026 to Friday, 5 June 2026 on a US calendar. That is five business days, and at a 7.5-hour working day the calculator reports 37.5 working hours — not the 40 a standard 8-hour assumption would give, and not the 120 that the raw calendar span contains. Change the country to New Zealand, where King’s Birthday falls on Monday 1 June, and the same range yields four business days and 30 hours. One holiday removes 7.5 hours of capacity from a week that still looks full on the calendar.
Frequently asked questions
How is this different from the Business Hours calculator?
That one takes two timestamps and measures the working time genuinely elapsed between them, down to the minute, with a lunch deduction — the right tool for an SLA clock or a ticket age. This one takes two dates and converts whole business days into hours at your chosen day length — the right tool for capacity planning and for translating a commitment written in days into one written in hours. If you know the clock times, use the other; if you only know the dates, use this.
Why does the hours-per-day figure matter so much?
Because it is the multiplier on everything. The same ten business days is 80 hours at an 8-hour day, 75 at 7.5 and 60 on a 6-hour part-time pattern — a spread of 20 hours from a single field. Contracts and SLAs frequently state a working-hours figure without defining the working day it assumes, which is exactly how two parties arrive at different deadlines from the same clause. Set it to your real day length, and pin it down in writing where it matters.
Does it count both the first and last day?
Yes, every business day in the range including both endpoints is counted as a whole working day, because the tool is measuring the capacity a span contains rather than the gap between two moments. If your convention excludes one endpoint, subtract one day’s worth of hours from the total — or use the Business Days Between Two Dates calculator, which exposes inclusive and exclusive toggles directly.
What this calculator does not do
A limitation you know about costs far less than one you find after the deadline. These are the specific things this tool cannot work out for you.
- Working hours are derived by multiplying working days by the day length you set. It is not a timestamp-level count — a part day at either end is not prorated.
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