Time Duration Calculator

How the duration is worked out

Both times are first converted into minutes since midnight — 9:15 AM becomes 555, and 5:45 PM becomes 1,065. Subtracting gives the span directly: 1,065 − 555 = 510 minutes. Every other form is the same number wearing different clothes: 510 minutes is 8 hours with 30 left over (8:30), 510 ÷ 60 = 8.50 decimal hours, and 510 × 60 = 30,600 seconds. Nothing is rounded until the decimal-hours display, which is rounded half-up to two places — the convention payroll charts use.

Overnight shifts: when the end is "earlier" than the start

A night shift from 10:00 PM to 6:30 AM breaks naive subtraction, because 6:30 AM is a smaller clock number than 10:00 PM. The fix is to read the end time as falling on the next day — add 24 hours (1,440 minutes) to it before subtracting: (390 + 1,440) − 1,320 = 510 minutes, the same 8 hours 30 minutes. That handling is switched on above, and when it kicks in the result says so. If you would rather be warned than have the calculator guess — for a same-day booking, say — switch it off and an end-before-start pair is flagged as an error instead. The overnight shift calculator is preset for exactly this case.

Breaks come off the top

The break field subtracts unpaid minutes — typically lunch — from the span before the results are shown. 9:00 AM to 5:30 PM is 8 hours 30 minutes gross; take a 30-minute lunch off and the payable time is 8 hours even, 8.00 decimal hours. Whether a break is unpaid, and how long it must be to count as one, depends on your employer and where you work — the calculator does the arithmetic, not the ruling.

From hours to pay

Decimal hours exist for one reason: pay is hours × rate, and 8:30 does not multiply. Once you have your decimal hours, a salary-to-hourly calculator works the other direction — turning a salary into the hourly rate those decimal hours get multiplied by, or an hourly wage into the annual figure.

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Frequently asked questions

How do I calculate the hours between two times by hand?

Convert both times to minutes since midnight and subtract. If the end minutes are smaller than the start minutes, nothing special happens at this level — the subtraction handles it, because you converted whole times rather than subtracting hours and minutes separately. The step-by-step guide also shows the classic borrow-an-hour method.

What is 8 hours 30 minutes in decimal hours?

8.50. Divide the minutes by 60: 30 ÷ 60 = 0.5, so 8 hours 30 minutes is 8.5 hours, displayed as 8.50. The traps are 15 minutes (0.25, not 0.15) and 45 minutes (0.75, not 0.45) — the chart lists all sixty minutes.

How are durations that cross midnight handled?

The end time is treated as next-day: 24 hours are added before subtracting, and the result notes that midnight was crossed. 10:00 PM to 6:30 AM is therefore 8 hours 30 minutes, not a negative number. You can switch this off if you want such inputs flagged as errors.

Should I subtract my lunch break?

If the break is unpaid, yes — most timesheets count only time worked. Enter the break in minutes and the net figure is what you would claim. Paid short breaks (often 5–20 minutes) usually stay in; your employer's policy and local rules decide, and they vary.

Is anything I type stored?

No. The calculation runs entirely in your browser; the times you enter never leave the page. See the privacy page.