Work Shift Hours Explained: Overnight & Split Shifts

Updated October 6, 2026

To calculate an overnight shift, count the time before midnight and after midnight, then subtract only unpaid breaks. To calculate a split shift, calculate each work period separately and add the results. Do not count an off-duty gap as work time or deduct it twice.

For example, 10:00 PM to 6:00 AM with a 30-minute unpaid break is 7 hours 30 minutes, or 7.5 hours, on a night without a clock change. Two work periods from 8:00 AM to noon and 4:00 PM to 8:00 PM total 8 hours if there are no unpaid breaks within those periods.

This guide covers shifts that cross midnight, split schedules, 12-hour shifts, clock changes, and recording hours across a workweek boundary. For the basic daytime method and decimal-hour chart, see how to calculate work hours.

Shift Length, Worked Hours, and Paid Hours

A schedule shows when you are expected to start and finish. Your time record shows what actually happened. Those figures may differ if you started early, finished late, took an unpaid meal period, or worked through a planned break.

• Elapsed shift length: time between the actual start and finish.
• Hours counted as work: the total after properly unpaid periods are excluded, including any paid rest breaks that count as work.
• Paid hours: hours used for pay, which may also include paid leave or other payments separate from hours worked.

Record actual times first. A label such as “8-hour shift” is not enough to calculate the final total.

How to Calculate Overnight Shift Hours

1. Record Both Dates

Write the start date beside the start time and the next date beside the finish time. A shift starting Monday at 10:00 PM and ending Tuesday at 6:00 AM lasts eight elapsed hours on an ordinary night.

2. Split the Shift at Midnight

From 10:00 PM to midnight is 2 hours. From midnight to 6:00 AM is 6 hours. Add them: 2 + 6 = 8 hours.

3. Subtract Only Unpaid Breaks

Subtracting a 30-minute unpaid meal period leaves 7 hours 30 minutes. Dividing 450 worked minutes by 60 gives 7.5 decimal hours.

For a shift lasting less than 24 hours, without a clock change, you can also convert both times to minutes after midnight. If the finish is earlier than the start, add 1,440 minutes to the finish before subtracting the start. This method assumes the finish is the next day; it does not identify the date for you.

Overnight Shift Examples

All examples below assume one overnight shift in the same time zone, without a daylight saving clock change.

If the start and finish show the same time, record the dates. That could mean zero elapsed time, 24 hours, or a longer period. Do not use a time-only result to resolve the ambiguity.

How to Calculate Split Shift Hours

A split shift has separate work periods with a gap between them. Calculate each period from its own start and finish rather than treating the first start and final finish as one continuous shift.

If the evening period includes a separate 30-minute unpaid meal break, the total becomes 4 + 3.5 = 7.5 hours. The four-hour gap is already excluded when you calculate the two periods separately. Do not enter it again as a break deduction.

An apparent gap is not automatically unpaid. If you must remain on duty, wait for assignments, or respond to calls, its treatment depends on the circumstances and applicable rules. The U.S. Department of Labor explains waiting and on-call time in its hours-worked guidance.

Does a 12-Hour Shift Mean 12 Worked Hours?

Not necessarily. From 7:00 AM to 7:00 PM is a 12-hour span. With a properly unpaid 30-minute meal period, the worked total is 11.5 hours. With two separate unpaid 30-minute meals, it is 11 hours.

Deduct breaks based on the actual record. For covered U.S. employees, short rest periods generally count as work, while a bona fide unpaid meal period generally requires being completely relieved of duties. Eating while answering work calls is not the same as being relieved from duty. See the Department of Labor’s break guidance. Local rules may differ.

Use the Break Time Calculator to check the deduction once you know which periods are properly unpaid.

Night Shifts During Daylight Saving Clock Changes

A time-only calculation can give the wrong result when clocks change during the shift. If the local clock moves forward one hour, a shift spanning that change has one fewer elapsed hour than ordinary clock subtraction suggests. If it moves back one hour, it has one extra hour.

For a 10:00 PM to 6:00 AM shift spanning a one-hour change:

• Ordinary night: 8 elapsed hours.
• Clocks move forward: 7 elapsed hours.
• Clocks move back: 9 elapsed hours.

Subtract any properly unpaid break from the corrected elapsed time. With a 30-minute unpaid break, those totals become 7.5, 6.5, and 8.5 worked hours respectively.

These examples assume the clock change occurs between the recorded start and finish. Use timestamps with dates and time-zone offsets for the actual record. The U.S. Department of Labor’s daylight saving examples explain why actual elapsed hours matter.

How to Record a Shift Across a Workweek Boundary

Keep the full start and finish timestamps, then allocate the worked time to the workweek in which it occurred. A start-date label may be useful for organizing a schedule, but it should not hide hours on the other side of the boundary.

For example, if the workweek starts Monday at midnight, a Sunday 10:00 PM to Monday 6:00 AM shift spans two workweeks. Before break deductions, 2 hours fall in the ending week and 6 hours in the new week. If an unpaid 30-minute meal occurs at 2:00 AM, the allocation becomes 2 hours and 5.5 hours.

Use the actual break timing when dividing a shift. For routine totals, the Timesheet Calculator can help add recorded hours; check boundary allocations separately if your schedule requires them.

Night Shift Premiums and Overtime Are Different

A night premium changes the pay rate for eligible night hours. Overtime concerns hours that qualify for an overtime payment. An overnight or 12-hour shift does not by itself establish the overtime total.

Under the U.S. FLSA, covered nonexempt employees generally receive overtime after 40 worked hours in a workweek; the Act does not itself require a night premium. Other rules and agreements may apply. See Night Work and Shift Work.

For an arithmetic example, four shifts of 11.5 worked hours total 46 hours. Under a simple 40-hour weekly threshold, that leaves 6 overtime hours. Use our Overtime Pay Calculator once the qualifying hours and applicable rate are established.

Before You Submit Your Shift Record

• Include dates for both ends of every overnight shift.
• Check AM and PM, especially noon and midnight.
• Record each split-shift period separately.
• Deduct each unpaid period once.
• Check clock changes and any time-zone differences.
• Keep exact minutes while adding shifts; convert and round the final total as required.
• Check shifts crossing the workweek boundary.

Frequently Asked Questions