Net work hours show how much of a shift remains after excluding unpaid or otherwise non-working breaks. This is useful for timesheets, workload planning, staffing and schedule checks. The important distinction is between elapsed clock time and net working time.
Elapsed time vs net work time
Elapsed time is the interval from the start of a shift to its end. Net work time is the elapsed interval minus breaks that should not count as work. A 09:00–17:00 shift is 8 elapsed hours; a 1-hour unpaid break leaves 7 net work hours.
Basic formula
Net work time = end time − start time − excluded breaksUse Tervilo's Hours Calculator
- Open the Tervilo Hours Calculator.
- Enter the start and end times.
- Use the overnight option if the shift crosses midnight.
- Read the elapsed hours and minutes.
- Subtract excluded breaks according to the real work or timesheet policy.
- Convert the result to decimal hours when required.
Example: standard workday
A 09:00 to 17:30 shift is 8 hours 30 minutes. Subtracting a 45-minute unpaid break leaves 7 hours 45 minutes, which is 7.75 decimal hours.
Why 45 minutes is not 0.45 hours
Decimal hours use fractions of an hour. Forty-five minutes is 45 ÷ 60 = 0.75 hours. Writing 7:45 as 7.45 hours would produce the wrong total in payroll or reporting calculations.
Example: multiple breaks
An 08:30–17:00 shift lasts 8 hours 30 minutes. If unpaid breaks total 50 minutes, net work time is 7 hours 40 minutes. In decimal form, 40 minutes is 0.6667 hours, so the approximate total is 7.67 hours.
Overnight shifts
A 22:00–06:00 shift crosses midnight. Its elapsed time is 8 hours. Use the overnight option so the end time is interpreted as occurring on the following day rather than as an earlier same-day time.
Break policy matters
A calculator cannot determine whether a break is paid, unpaid, mandatory or treated differently by a particular employer. Apply the actual timesheet or work policy instead of automatically subtracting a standard break.
Example: flexible remote-work breaks
A remote worker may take several short breaks instead of one long lunch. For a timesheet calculation, count only the periods that the applicable policy says are excluded. A default one-hour deduction is not automatically correct.
Net hours are not productivity
Net work hours measure time accounting. They do not measure output or performance. Meetings, interruptions, task switching and the difficulty of the work can make two people with the same net hours produce very different results.
Keep recurring records consistent
For repeated timesheets, record start, end and excluded-break time in a consistent format. Decide whether the destination system expects hours and minutes or decimal hours, then use the same conversion method each time.
Check daylight-saving and time-zone cases
Simple clock arithmetic may not be sufficient when a shift crosses a daylight-saving transition or spans time zones. Those cases require date and time-zone-aware handling rather than assuming every elapsed hour is represented by a simple clock difference.
Check before reporting
Verify the start and end dates, overnight setting and break total. Make sure no break was subtracted twice and that decimal conversion was performed by dividing minutes by 60.
Common mistakes
- Subtracting a break twice.
- Treating 30 or 45 minutes as a decimal “.30” or “.45”.
- Forgetting an overnight date change.
- Using a default break that does not match the policy.
- Confusing net hours with productivity.
When a simple calculation is not enough
Payroll can involve overtime, split shifts, rounding, paid breaks and different rates. The basic calculation establishes elapsed and net time; the final payroll treatment should follow the applicable rules.
Quick verification checklist
- □ Start and end times are correct.
- □ Overnight status is correct where needed.
- □ Each excluded break is counted once.
- □ Decimal hours are converted correctly.
- □ The actual work policy is known.
Quick answer
Calculate net work hours by finding elapsed time between start and end, then subtracting breaks that the applicable policy excludes. Use Tervilo's Hours Calculator for the clock interval and convert minutes to decimal hours only after the net duration is known.