Hours Calculator

Subtract the times, then subtract the break

Start with the raw elapsed time: end time minus start time. A shift from 09:00 to 17:30 is 8 hours 30 minutes. Then remove unpaid breaks. A 30 minute lunch leaves 8 hours 0 minutes. Doing these as two separate steps matters, because the break is a duration rather than a clock time — subtracting "30 minutes" from "17:30" produces 17:00, which is a different (and wrong) operation.

In decimal terms the same calculation is 8.50 − 0.50 = 8.00. Keeping both representations in view is the simplest way to catch a slip: if the hours-and-minutes result and the decimal result disagree, one of them is wrong.

Overnight and early morning shifts

When the finishing time is earlier than the starting time, the shift has crossed midnight. A straightforward subtraction gives a negative number, which is the classic sign of this case. Adding 24 hours corrects it: a 22:00 to 06:00 shift computes as 6 − 22 = −16, then −16 + 24 = 8 hours. This calculator applies that correction automatically, so night shifts and split shifts do not need special handling from you.

Decimal hours versus hours and minutes

Decimal hours express the same duration as a single number: 7 hours 45 minutes is 7.75 hours, obtained by dividing 45 by 60. Payroll prefers this form because the gross pay is then one multiplication — hours × rate. The trap is reading "7.45" as 7 hours 45 minutes when it actually means 7 hours 27 minutes. If a figure came from a payroll system, it is decimal; if it came from a wall clock, it is minutes. Converting between the two is exactly what the third mode above does.

Rounding rules and the seven minute rule

Many employers round punch times to the nearest quarter hour. US federal guidance treats small, hard-to-record increments as not compensable, and the practice that grew out of it rounds in seven minute blocks: 1 to 7 minutes past the quarter rounds back, 8 to 14 minutes rounds forward. The important constraint is direction — rounding must not systematically shave time off the employee's side over a pay period. If you are checking a payslip and the totals drift in one direction week after week, compare the unrounded hours from this calculator with the rounded figures on the slip.

Combining several days into a weekly total

For a weekly total, add the decimal hours rather than the clock times: day totals of 8.25, 7.75, 8.00, 8.50 and 6.00 come to 38.50 hours. Adding the same days as clock times (8:15, 7:45, 8:00, 8:30, 6:00) means carrying 60s rather than 100s between columns, which is where most manual arithmetic errors appear. Convert first, add second.

Checking a payslip

Enter each day's start and end times with the break you actually took, write down the decimal hours, and add them up. Multiply the total by your hourly rate and compare it with gross pay before tax. Because everything here runs locally in your browser, you can check a full week of shifts without sending your working hours anywhere.

Quoting a job or planning a shift

The same arithmetic serves the other direction: a supplier says the work will take 14 hours 20 minutes and you want to know whether that fits between 08:00 and 22:00. The add-and-subtract mode answers it directly, and the time-between mode confirms the resulting window, including any breaks you need to schedule.

Time zones and travel

This page works in local wall-clock arithmetic: it deliberately does not shift for time zones. If you are combining a shift in one city with a call in another, convert both to the same zone first — our currency pages are built on the same principle of showing the raw reference values and letting you compare them yourself.