How many hours is that?

How to add up hours on a time card

Working out hours from a clock-in and clock-out time sounds trivial until you actually do it by hand. The problem is that time is base-60, not base-10: the gap between 9:50 and 10:10 is twenty minutes, not sixty, and our usual decimal instincts get it wrong. The reliable method is to convert both times to minutes since midnight, subtract, then convert the result back. A 09:00 start is 540 minutes; a 17:30 finish is 1,050 minutes; the difference is 510 minutes, which is 8 hours and 30 minutes. Take off a 30-minute unpaid lunch and you are left with 8 hours of paid work. That is exactly the arithmetic this tool performs, so you never have to borrow across the hour boundary in your head.

Why payroll wants decimal hours

Almost every payroll system multiplies hours by an hourly rate, and you cannot cleanly multiply "8 hours 30 minutes" by a dollar figure. That is why timesheets are converted to decimal hours, where the minutes become a fraction of an hour. Half an hour is 0.5, a quarter hour is 0.25, and ten minutes is 0.166..., which payroll usually rounds to two decimals (0.17). The tool shows both forms side by side: the human-readable "8h 30m" and the payroll-ready "8.50", so you can copy whichever one your timesheet asks for. If you add an hourly rate, it also multiplies the net decimal hours by that rate to give a quick gross-pay estimate before tax and deductions.

Overnight shifts, breaks, and rounding

Night-shift and hospitality workers run into the classic trap where the finish time looks smaller than the start time: a shift from 22:00 to 06:00 naively reads as "negative sixteen hours." The fix is to recognise the shift crossed midnight and add 24 hours to the end, giving the correct 8 hours. This calculator detects that automatically whenever the end time is at or before the start time. Breaks matter too: most jurisdictions treat meal breaks as unpaid, so the minutes you enter in the break field are subtracted from the total before pay is worked out. Rounding is the last wrinkle. Some US employers use quarter-hour rounding under the so-called 7-minute rule, where anything in the first seven minutes of a quarter rounds down and the rest rounds up; the rounding must be neutral so it does not consistently favour the employer. This tool reports exact minutes and leaves the rounding policy to you, because the correct rule depends entirely on where you work and what your contract says.

Related calculators

Need to count whole days or business days instead of hours within a day? Use the days-between tool for the gap between two dates, or the working-days calculator to exclude weekends and public holidays. If your shift spans time zones, convert it first with the time zone converter.

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