How to calculate overnight shift hours

Updated November 14, 2026 · Worked examples use whole minutes

Start with the date you clocked in. A Tuesday shift that starts at 10 pm and finishes at 6 am on Wednesday includes two hours before midnight and six after. Together they give an eight-hour span on an ordinary night.

Calculate it step by step

1. Enter the clock-in and clock-out times on the row for the starting date. Check that the end belongs to the following day.
2. Add up the minutes of unpaid breaks actually taken during the shift. Enter them once, even if a break crossed midnight.
3. Check the resulting duration against the shift record. Each row represents one shift shorter than 24 hours.

Worked example

From 9:45 pm to midnight is 2 hours 15 minutes. Midnight to 5:30 am adds 5 hours 30 minutes. Subtract a 25-minute unpaid break from the 7 hours 45 minutes between clock-in and clock-out. The timecard records 7 hours 20 minutes.

Check your own shifts in the time card calculator

Which date gets the shift, and what if the clocks change?

This calculator groups the whole shift under its starting date. A Sunday night shift therefore appears in the week that includes that Sunday. If your workplace splits hours at midnight, compare the two sides of the boundary separately.

On a night when clocks change, the time shown on the wall can skip or repeat an hour. This sheet uses the clock readings you enter. Check the original time records and their time zone before relying on that shift’s total. The same check applies if you changed time zones during a shift.

Further reading

• NIST guide to daylight saving time in the US
• UK clock-change dates and times