CalcToolVault

Time Duration Calculator

Add up hours and minutes, work out the time between two clock times, and convert to decimal hours for timesheets.

Your details

min

Totals

days
$

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This calculator runs entirely on your device. Nothing you enter is uploaded, stored, or sold. How this works

Duration

8h 0m

8.00 decimal hours

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Includes your inputs, the full breakdown, and every row of the table.

Decimal hours

8.00

Total minutes

480

Over 5 days

40h 0m

Breakdown
Start
09:15
End
17:45
Gross duration
8h 30m
Less break
- 30m
Net worked
8h 0m
The same duration in other units
UnitValue
Hours and minutes8h 0m
Decimal hours8.0000
Minutes480
Seconds28,800
Total over 5 days40.00 hours

What this means

  • Timesheets and payroll systems want decimal hours, not hours and minutes. Forty-five minutes is 0.75 hours, not 0.45 — this is the single most common timesheet error.
  • If you work overnight, simply enter the end time as it appears on the clock and the calculation handles the rollover.

How the time duration calculation works

Time arithmetic is base sixty, which is why it resists mental shortcuts. The most frequent and expensive mistake is treating minutes as decimals: writing seven hours and thirty minutes as 7.30 rather than 7.5 understates the shift by twelve minutes, and repeated across a fortnight and a team it becomes real money. Converting to decimal hours is simply the minutes divided by sixty.

Shifts crossing midnight cause the second common failure. Subtracting an end time of 02:00 from a start of 22:00 produces a negative number unless you recognise the rollover and add a full day. This calculator detects that case automatically, so an overnight shift can be entered exactly as it appears on the clock.

Frequently asked questions

How do I convert minutes into decimal hours?

Divide by sixty. Fifteen minutes is 0.25, thirty is 0.5, forty-five is 0.75. The trap is writing 7:45 as 7.45 in a payroll field when it should be 7.75 — a difference of eighteen minutes on a single shift.

Does this handle overnight shifts?

Yes. If the end time is earlier than the start time, it is treated as the following day and a full twenty-four hours is added before subtracting. A shift from 22:00 to 06:00 correctly returns eight hours rather than a negative figure.

Should breaks be deducted?

Unpaid breaks should be, and that is what the break field does. Paid breaks stay in the total. Rules on when a break becomes mandatory and whether it must be paid vary considerably by jurisdiction and by the length of the shift.

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Disclaimer. This calculator is provided for general information and educational purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Results are estimates based on the inputs you provide and the assumptions described above. Confirm any figure with a qualified professional before acting on it.