8-Hour Shift Calculator
Plan a clock-out time for eight paid hours and an unpaid break. Enter a 24-hour start time and unpaid break to find the expected end clock time.
How the result changes
Only start hour changes; all other inputs stay at your current values. Each dot represents one whole-number input. This is not a forecast of real-world outcomes.
About this calculation
An eight-hour paid shift lasts longer than eight clock hours when it includes an unpaid break. This calculator adds the break to eight paid hours and reports the resulting clock-out as a 24-hour decimal time. Find start and end times for an eight-hour shift.
Formula
clock-out = start clock time + 8 paid hours + unpaid break, modulo 24 hours
Worked example
With Start hour: 9 24-hour clock, Start minute: 0 min, Unpaid break: 30 min, clock-out hour is 17.5 24-hour decimal.
Inputs and units
Enter the start as a whole 24-hour clock hour and minute, then the total unpaid break in minutes. A 9:00 start with a half-hour unpaid break is represented by 9, 0, and 30.
- Start hour (24-hour clock): Enter the whole clock hour from 0 through 23.
- Start minute (min): Enter the minute within the start hour, from 0 through 59.
- Unpaid break (min): Enter the total unpaid break minutes during the shift.
Calculation and worked example
Convert the start to minutes after midnight, add 480 paid minutes and the unpaid-break minutes, then take the remainder after a 1,440-minute day. Divide by 60 for the decimal-clock output. Elapsed hours equal eight plus break minutes divided by 60 In compact notation, clock-out = start clock time + 8 paid hours + unpaid break, modulo 24 hours.
Starting at 09:00 with a 30-minute unpaid break leads to 17:30 clock-out, displayed as 17.5 in 24-hour decimal notation. The total span is 8.5 hours and paid time remains exactly 8 hours.
How to use the answer
Clock-out hour is a time of day, while elapsed and paid outputs are durations. A result of 1.5 on the clock means 01:30 after midnight, not one and a half hours of work.
Plan a standard shift or compare alternative unpaid-break lengths. If a start late at night crosses midnight, the modulo operation correctly shows next day's clock time, though it does not display the calendar date.
Assumptions and checks
The shift contains exactly eight paid hours and one aggregate unpaid break. The tool does not apply overtime law, paid rest periods, time zone changes, daylight-saving transitions, or employer-specific rounding rules.
Do not treat 17.5 as 17:50; decimal .5 hour is 30 minutes. A paid break should not be entered as unpaid, and a 24-hour clock start of 9 means 09:00, not 21:00.
Subtract the start clock time from clock-out, allowing one day if it wraps. The resulting elapsed hours should equal 8 plus the entered break divided by 60.
Common questions
What does the clock-out hour result represent?
It is the expected 24-hour decimal clock time when eight paid hours and the entered unpaid break have elapsed.
What should I check before relying on this result?
Check whether the break is truly unpaid and whether the shift crosses a date or daylight-saving change that requires separate handling.
Inputs
- Start hour (24-hour clock)
- Start minute (min)
- Unpaid break (min)