BYTETOOLS

Business Hours Calculator

Count working hours between two timestamps against your opening hours, working days, lunch break and public holidays — the arithmetic behind SLA clocks.

Working days
25h 45m
Business hours
1545
Business minutes
3.68
Business days
92h 45m
Calendar hours

Day by day

A full working day here is 7h 00m (09:00–17:00 less the 12:30–13:30 break).

DateStatusCounted windowHours
Mon, Jan 5, 2026Open14:30–17:002h 30m
Tue, Jan 6, 2026Open09:00–17:007h 00m
Wed, Jan 7, 2026Open09:00–17:007h 00m
Thu, Jan 8, 2026Open09:00–17:007h 00m
Fri, Jan 9, 2026Open09:00–11:152h 15m

This is the arithmetic behind an SLA clock: the elapsed time is intersected with each day’s opening window rather than measured end to end, so a ticket raised at 16:45 on Friday and answered at 09:15 on Monday has used 30 minutes of a 9-to-5 service window, not 64 hours. Both timestamps are treated as being in the same time zone — convert them first if your team and your customer are in different ones. Everything runs in your browser.

What is the Business Hours Calculator?

Elapsed time and business time are not the same thing. A ticket raised at 16:45 on Friday and answered at 09:15 on Monday has been open for 64 hours but has used only 30 minutes of a nine-to-five service window.

  • Day-by-day intersection of the interval with your opening hours
  • Any combination of working days, not just Monday to Friday
  • Optional unpaid break subtracted from every working day
  • Pasted holiday list, with comments and trailing names accepted
  • Business hours, business minutes, equivalent working days and raw calendar hours
  • Full audit table showing the counted window for each date, copyable as CSV

How to use the Business Hours Calculator

  1. 1

    Enter the start date and time, and the end date and time.

  2. 2

    Set when the working day opens and closes, and tick the days of the week you work.

  3. 3

    Tick the break option and set its times if you subtract an unpaid lunch from each day.

  4. 4

    Paste any public holidays, one YYYY-MM-DD per line — a trailing name is fine.

  5. 5

    Read the business hours total, then check the day-by-day table and copy it as CSV.

About the Business Hours Calculator

Elapsed time and business time are not the same thing. A ticket raised at 16:45 on Friday and answered at 09:15 on Monday has been open for 64 hours but has used only 30 minutes of a nine-to-five service window. This calculator walks the interval day by day and intersects each day with your actual opening hours to give the business figure.

You control everything that matters: the start and end timestamps, which days of the week you work, when the working day opens and closes, an optional unpaid break subtracted from each day, and a pasted list of public holidays to skip. The day-by-day breakdown shows exactly which window was counted on each date, so the total is auditable rather than mysterious.

Results come as business hours and minutes, the equivalent in full working days, and the raw calendar hours for comparison. Both timestamps are treated as being in the same time zone, so convert them first if your team and your customer are not. Everything is computed in your browser and nothing is uploaded.

Frequently asked questions

How do you calculate business hours between two dates?

You cannot subtract one timestamp from the other. You walk each calendar day in the interval, keep only the part that overlaps that day's opening window, drop weekends and holidays, subtract any break, and add up what is left. That is exactly what this tool does.

What is an SLA clock and how does it relate to this?

An SLA response or resolution target is measured in business hours, so the clock only runs during your service window. This calculator performs the same arithmetic, which makes it useful for checking whether a ticket really breached its target.

Does it handle public holidays?

Yes. Paste them one per line as YYYY-MM-DD. A trailing name like 2026-12-25 Christmas Day is accepted, and lines starting with a hash are ignored, so you can keep a commented list and reuse it.

What about time zones?

Both timestamps are treated as being in the same time zone as your opening hours. If your customer is in another zone, convert their timestamp to yours first — otherwise you will count the wrong part of the working day.

Can I use opening hours that cross midnight?

Not in this tool. The working day must end after it starts, so an overnight shift from 22:00 to 06:00 is not supported and the page tells you so rather than returning a wrong number.

How many business hours are in a working day?

It depends on your window. A nine-to-five day with a one-hour unpaid lunch is seven business hours. The tool states the figure it is using for your settings, and the business days total divides the result by it.

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