Math

Hours calculator.

The time between two times, minus breaks — in hours, minutes and decimal.

From clock times to a timesheet

Enter a start and end time and the calculator returns the gap, subtracts any unpaid break, and shows the result two ways: as hours and minutes, and as decimal hours — the format payroll and invoicing systems expect, where 8 hours 30 minutes is 8.5, not 8.30. The conversion trips people up because there are 60 minutes in an hour, not 100: to convert minutes to decimal, divide by 60 (45 minutes ÷ 60 = 0.75). If the end time is earlier than the start, the calculator assumes the shift ran past midnight and counts it as overnight, so a 10 pm to 6 am shift comes out as 8 hours. It's built for timesheets and shift totals; for a single day's worth of multiple entries, run each and add the decimals. To count whole days instead of hours, see the date calculator.

A worked example

Say a shift runs from 08:45 to 17:20 with a 30-minute unpaid lunch. The gap between the two clock times is 8 hours 35 minutes; take off the break and you are left with 8 hours 5 minutes. Converted for payroll that is 5 ÷ 60 = 0.0833, so the decimal total is 8.08 hours. Entering 8.05 instead — the mistake the 60-versus-100 confusion invites — would under-pay the shift by nearly two minutes every day, which adds up across a month.

Adding up a week

Timesheets are totalled in decimal hours precisely because decimals add cleanly and hours-and-minutes do not. Run each shift through the calculator, note the decimal figure, then sum those: 8.08 + 7.75 + 8.25 + 6.50 + 8.00 comes to 38.58 hours for the week. If you try to add 8h05m + 7h45m in your head you have to keep carrying at 60, which is where errors creep in.

Many payroll systems treat hours beyond a weekly threshold as overtime at a higher rate, but the threshold, the rate and whether it is calculated daily or weekly all depend on your country, industry and contract — check your own terms rather than assuming the common 40-hour figure applies.

Rounding and breaks

Employers often round clock-in and clock-out times to the nearest quarter hour. Rounding is generally only acceptable where it is neutral over time — rounding always downwards systematically shortchanges staff. If your workplace rounds, apply it to the clock times before subtracting the break, not to the final decimal, or the rounding compounds.

Whether a break is paid matters as much as its length. Enter only unpaid breaks; paid rest breaks should stay inside the total. If a shift has several unpaid breaks, add their minutes together and enter the combined figure.

FAQ

How do I calculate hours between two times?
Enter the start and end time; the calculator returns the duration, minus any break, in hours and minutes and as decimal hours. If the end is before the start it's treated as an overnight shift.
How do I convert minutes to decimal hours?
Divide the minutes by 60. So 30 minutes is 0.5, 15 minutes is 0.25, and 45 minutes is 0.75 — which is why 8 hours 30 minutes is written as 8.5 decimal hours.
What is 8 hours 15 minutes in decimal?
8.25 hours. Divide the minutes by 60 to get the decimal part: 15 ÷ 60 = 0.25. The common quarter-hour values are 15 minutes = 0.25, 30 minutes = 0.5 and 45 minutes = 0.75.
How do I add up hours for a whole week?
Convert each shift to decimal hours first, then add the decimals. Adding 8.08 + 7.75 + 8.25 is straightforward, whereas adding 8h05m + 7h45m + 8h15m means carrying at 60 and is where most timesheet errors come from.
Does it handle overnight shifts?
Yes. If the end time is earlier than the start time, the calculator assumes the shift crossed midnight, so 10 pm to 6 am is counted as 8 hours rather than a negative result.

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