How to Calculate Overnight Work Hours
Working across midnight can make a time card harder to read. A shift that starts at 10:00 PM and ends at 6:00 AM finishes on the following day, even though the end time looks smaller than the start time.
The easiest method is to calculate the time before midnight, add the time after midnight, and subtract any unpaid breaks.
For example:
10:00 PM to 6:00 AM = 8 hours
With a 30-minute unpaid break:
8 hours − 30 minutes = 7 hours 30 minutes
You can check a shift using the free HandyMetric Time Card Calculator.
How to calculate a shift that crosses midnight
Split the shift into two parts:
- Time from the start of the shift to midnight.
- Time from midnight to the end of the shift.
Then add them together.
For a shift from 9:30 PM to 5:45 AM:
| Part of the shift | Duration |
|---|---|
| 9:30 PM to midnight | 2 hours 30 minutes |
| Midnight to 5:45 AM | 5 hours 45 minutes |
| Total elapsed time | 8 hours 15 minutes |
This is the elapsed shift time before deducting unpaid breaks.
Subtract unpaid breaks
Once you know the elapsed shift time, subtract the break minutes that should be excluded from work time.
For the same 9:30 PM to 5:45 AM shift with a 45-minute unpaid break:
8 hours 15 minutes − 45 minutes = 7 hours 30 minutes
The formula is:
Work time = elapsed shift time − unpaid breaks
Do not automatically subtract every break. Paid breaks remain part of the time counted in this calculation. Whether a break can legally be unpaid depends on applicable requirements and the circumstances.
Read our guide to calculating work hours with unpaid breaks for more examples.
The 24-hour-clock method
You can also calculate an overnight shift using a 24-hour clock.
For a shift from 22:00 to 06:00 the next day, treat the end as 24 hours plus 6 hours:
(24:00 − 22:00) + 06:00 = 08:00
Here, 08:00 represents a duration of eight hours, not an 8:00 AM clock-in time.
Another way is to convert the clock times into minutes after midnight:
- Start: 22 × 60 = 1,320 minutes
- End: 6 × 60 = 360 minutes
- Add one day to the end: 360 + 1,440 = 1,800 minutes
- Subtract the start: 1,800 − 1,320 = 480 minutes
480 minutes ÷ 60 = 8 hours
This approach assumes the shift ends the following day and that no clock change affects the elapsed time.
Overnight shift examples
These examples assume the end time is on the next day and no daylight saving change occurs.
| Start | End next day | Unpaid break | Work time |
|---|---|---|---|
| 10:00 PM | 6:00 AM | 30 minutes | 7h 30m |
| 9:30 PM | 5:45 AM | 45 minutes | 7h 30m |
| 11:00 PM | 7:15 AM | 30 minutes | 7h 45m |
| 8:00 PM | 4:00 AM | 60 minutes | 7h 00m |
| 11:45 PM | 12:15 AM | None | 0h 30m |
Use the actual break duration for your shift. Do not deduct a standard break if it was not taken or should count as paid time.
Convert overnight work time to decimal hours
After subtracting unpaid breaks, convert the remaining minutes into a fraction of an hour:
Decimal hours = whole hours + minutes ÷ 60
For 7 hours 30 minutes:
7 + 30 ÷ 60 = 7.50 hours
For 7 hours 45 minutes:
7 + 45 ÷ 60 = 7.75 hours
You can use the Hours & Minutes to Decimal Calculator for this step.
Remember that 7.30 decimal hours is not 7 hours 30 minutes. For a conversion chart and more examples, read how to convert minutes to decimal hours.
Enter an overnight shift in HandyMetric
In the Time Card Calculator:
- Enter the start time in 24-hour format. For 10:00 PM, type 2200.
- Enter the end time. For 6:00 AM, type 0600.
- Enter the unpaid break in whole minutes.
- Select Calculate hours.
The fields insert the colon as you type. When the end time is earlier than the start time, the calculator treats it as ending the next day and adds “next day” to the daily result.
Enter the entire shift on the row for the day it starts. This is a way to organize the entry; the calculator does not split that shift between calendar days or payroll workweeks.
What happens when the clocks change?
A shift crossing a daylight saving time change may have a different actual duration from ordinary clock-time subtraction.
For example, where clocks move forward from 2:00 AM to 3:00 AM, a shift from 10:00 PM to 6:00 AM spans seven elapsed hours, assuming that clock change occurs during the shift.
Where clocks move back from 2:00 AM to 1:00 AM, the same displayed start and end times span nine elapsed hours.
These examples assume the same location and no other time-zone change. Not every location observes daylight saving time.
The HandyMetric Time Card Calculator does not adjust for daylight saving changes. It uses clock times without dates or time zones. Check the actual elapsed time using dated records for those shifts.
What if the shift crosses a workweek boundary?
An overnight shift may begin in one payroll workweek and end in another.
For example, if the workweek ends at midnight on Sunday, a shift from Sunday at 10:00 PM to Monday at 6:00 AM crosses that boundary.
The hours and any unpaid break may need to be allocated to the appropriate workweek according to the applicable requirements and timekeeping arrangements.
HandyMetric does not perform this allocation automatically. Its weekly total adds the shifts entered; assigning an entire shift to one row does not determine how payroll should classify it.
Common mistakes to avoid
- Subtracting the end from the start without accounting for midnight. An end time of 06:00 can be later than a start time of 22:00 when it falls on the next day.
- Using 10:00 for 10:00 PM. On a 24-hour clock, 10:00 means 10:00 AM. Use 22:00 for 10:00 PM.
- Deducting paid breaks. Only deduct break time that should be excluded from work time.
- Ignoring a daylight saving change. Ordinary clock-time subtraction may be off by an hour.
- Assuming an overnight shift automatically qualifies for extra pay. Night premiums and overtime depend on applicable rules and employment arrangements.
- Entering identical start and end times for a 24-hour shift. HandyMetric treats identical times as zero hours and supports shifts shorter than 24 hours.
Frequently asked questions
How many hours is 10 PM to 6 AM?
It is eight hours before unpaid breaks, assuming the shift ends the next day and no daylight saving change occurs.
With a 30-minute unpaid break, the work time is 7 hours 30 minutes.
How many hours is 11 PM to 7 AM?
It is eight hours before unpaid breaks, under the same assumptions.
Does an overnight shift count as two workdays?
It crosses two calendar dates, but that does not by itself determine how it should be recorded for payroll or overtime. Check the applicable workday, workweek, and timekeeping requirements.
Can HandyMetric calculate a shift longer than 24 hours?
No. The current calculator supports one continuous shift per day, shorter than 24 hours. Identical start and end times count as zero hours.
Does working at night automatically mean overtime?
No. Working overnight does not, by itself, establish overtime eligibility. Relevant hours, exemptions, state requirements, and employment arrangements must be considered separately.
Check your overnight work hours
Use the free HandyMetric Time Card Calculator to calculate a shift crossing midnight and deduct unpaid breaks.
If you already know the duration, use the Hours & Minutes to Decimal Calculator to convert it into decimal hours.
This guide provides general information, not individualized legal or payroll advice.
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