How to use the night shift hours calculator
- Enter when your shift starts and ends. If the end time is earlier than the start time, the shift ends the next day.
- Enter when night hours begin and end. The example window is only a starting point, so use the window your employer or contract defines.
- Enter any unpaid break and choose whether it comes out of regular hours or night hours first. Add the number of shifts if you work the same one several times.
- Optionally add your base hourly rate and the night differential, as dollars per hour or a percent of base, to see the pay.
Formula
Shift length = end - start, plus 24 hours if the end is earlier than the start
Night hours = the part of the shift that falls inside the night window
Regular hours = shift length - night hours
Pay = base rate x paid hours + differential x night hours
The night window can cross midnight. The tool counts overlap with the window on both sides of midnight, so a shift that starts before the window and ends after it is handled correctly.
A 22:00 to 06:30 shift
The shift is 8 hours 30 minutes long. With night hours from 22:00 to 06:00, 8 hours are night hours and the last 30 minutes, 06:00 to 06:30, are regular hours. With a 30 minute unpaid break taken out of regular hours first, the paid time is 8 hours, all of it night time.
At $20 an hour with a $2 an hour night differential, the pay for the unbroken 8.5 hours is 8.5 x $20 + 8 x $2 = $186.00. A shift from 20:00 to 04:00 has 6 night hours and 2 regular hours.
Shifts that cross midnight
Counting hours across midnight is where mistakes happen, because the clock resets. The tool treats the end time as the next day when it is earlier than the start, then measures the overlap with the night window, which may itself cross midnight.
A shift of exactly 24 hours cannot be entered, because the same start and end time looks like zero. Enter a shift as two parts if you need to.
Different definitions of night
Employers and contracts define night hours in many ways. Some pay a differential for each hour inside a window, some for the whole shift if a share of it falls inside the window, and some by clock time of the start. This tool uses the hour by hour overlap, so check that it matches your own policy.
For the pay side of differentials, use the shift differential pay calculator. To total hours across a week, the hours calculator and the time card calculator are useful, and the time duration calculator measures any span.
Assumptions and limits
- The night window is a starting example that you change to match your own policy.
- The break is taken out of the hours you choose first, and the rest from the other kind.
- Overtime and legally required breaks are not modeled.
- Rules vary by employer and contract. This is not legal or payroll advice.
Frequently asked questions
How do I calculate hours for a shift that crosses midnight?
Add 24 hours to the end time if it is earlier than the start time, then subtract. A shift from 22:00 to 06:30 is 8 hours 30 minutes, which is 8.5 hours.
How many of my hours count as night hours?
It depends on the window your employer defines. The tool counts the minutes of the shift that fall inside the window you enter. For a 22:00 to 06:30 shift and a window from 22:00 to 06:00, that is 8 hours.
Does the unpaid break reduce night hours?
You choose. Taking the break out of regular hours first keeps your night hours intact, and taking it out of night hours first lowers them. Use whichever your policy states.
Can I use this for several shifts?
Yes, for identical shifts. Enter the number of shifts and the tool multiplies the hours and the pay.