Quick answer: Working hours are the time between starting and finishing work, minus any unpaid breaks. Start with the clock times, calculate the elapsed duration, and subtract breaks before recording the payable total.
Try it: Open the free BuzBolt Time Calculator. No signup is required.
A reliable method for every shift
Start with the actual times recorded, then calculate the elapsed duration. Subtract only the unpaid break time that you have chosen to exclude. For a shift crossing midnight, treat the finishing time as the next day. Finally, keep the total in minutes until you have completed your calculations.
The working formula is:
Net worked minutes = elapsed minutes − recorded unpaid break minutes
To express the answer in hours and minutes, divide by 60. The whole-number result is hours; the remainder is minutes. For a decimal-hour result, divide the full minute total by 60 and round only for display.
Worked example: a normal day
A person starts at 08:30, finishes at 17:15 and records a 30-minute unpaid break. The interval from 08:30 to 17:15 is 8 hours 45 minutes, or 525 minutes. After subtracting 30 minutes, the net duration is 495 minutes = 8 hours 15 minutes = 8.25 decimal hours.
| Step | Calculation | Result |
|---|---|---|
| Elapsed duration | 08:30 to 17:15 | 8h 45m |
| Convert to minutes | 8 × 60 + 45 | 525 minutes |
| Remove unpaid break | 525 − 30 | 495 minutes |
| Convert to normal hours | 495 ÷ 60 | 8h 15m |
| Convert to decimal hours | 495 ÷ 60 | 8.25 hours |
Worked example: an overnight shift
Start at 22:30 and finish at 06:15 the next day. Count 90 minutes to midnight and 375 minutes after midnight. That is 465 minutes altogether, or 7 hours 45 minutes. If there is a recorded 30-minute unpaid break, the net duration is 7 hours 15 minutes.
This convention works for overnight intervals of less than 24 hours. When a shift could cover more than one calendar day, you need both dates as well as the clock times. A simple calculator with only two clock-time fields cannot establish whether an interval lasted 7 hours or 31 hours.
Add an entire week without rounding errors
Convert every day's net result to minutes first. Example daily totals of 7h 45m, 8h 10m, 6h 30m, 8h 00m and 7h 35m become 465, 490, 390, 480 and 455 minutes. Added together, they equal 2,280 minutes or 38 hours.
Why not sum rounded decimals? Because 7h 35m is 7.5833… hours, not exactly 7.58 or 7.6. Repeated rounding may introduce differences between a calculated total and the original time records.
Using a spreadsheet
If A2 is a true start-time cell and B2 is a true end-time cell, =MOD(B2-A2,1)*24 calculates the elapsed duration in decimal hours for an interval shorter than 24 hours. If C2 stores a break in minutes, use =MOD(B2-A2,1)*24-C2/60. Use actual date-time values for longer intervals.
Common mistakes
- Treating 8 hours 30 minutes as 8.30 decimal hours. The correct decimal is 8.50.
- Forgetting that an earlier finish time may be on the next day.
- Deducting a break twice or assuming every break is unpaid.
- Rounding daily decimal hours before calculating the weekly total.
- Calling the calculated duration “paid hours” without knowing the applicable arrangement.
BuzBolt can calculate durations and decimal hours, but it cannot determine workplace rules or contractual entitlements. Review the input times, break treatment and any recordkeeping process that applies to your situation.
A quick checklist before you save a time result
Check the start and end times in the correct 12-hour or 24-hour format. Confirm whether the end occurs the same day or the following day. Enter only the unpaid break duration you intend to deduct, and check that it does not exceed the elapsed interval. If you need a weekly result, add individual net durations in minutes before converting to decimal hours.
A useful record shows both 8h 15m and 8.25 decimal hours where a decimal representation is needed. Those two numbers can look different, but represent exactly the same duration. Keep the original clock-time entries available if someone needs to understand how you reached the total.
When a simple calculator is not enough
A shift with multiple breaks, date changes over more than one day, or special workplace arrangements may require a more detailed time record. The BuzBolt Time Calculator is intended for straightforward duration and conversion tasks. It does not decide whether a period counts as paid work. Treat such classification as a separate question.
More reading
- How to Calculate Work Hours With a Lunch Break
- Overnight Shift Hours: Calculating Time Across Midnight
This article explains time arithmetic, not employment entitlements or payroll policy.
BuzBolt provides general educational tools and explanations. Check your inputs and confirm any legal, tax, accounting or workplace-specific requirements independently where relevant.