The short formula
Overnight shift hours = time from the start to midnight + time from midnight to the end − unpaid break time.
Worked example: 10:00 PM to 6:30 AM
- 10:00 PM to midnight is 2 hours.
- Midnight to 6:30 AM is 6 hours 30 minutes.
- The elapsed shift is therefore 8 hours 30 minutes.
- Subtract a 30-minute unpaid break to get 8 paid hours.
Five identical shifts total 40 paid hours. Whether any of those hours count as overtime depends on the employee’s location, contract, pay period, and workplace policy.
Convert minutes to decimal hours carefully
Payroll-style decimal hours are fractions of 60, not clock notation. Fifteen minutes is 0.25 hours, 30 minutes is 0.50 hours, and 45 minutes is 0.75 hours. A result of 8 hours 30 minutes is 8.5 hours, not 8.30 hours.
When the simple total is not enough
Paid breaks, split shifts, daylight-saving transitions, minimum shift payments, daily overtime, rounding rules, and on-call time can change a payroll result. Use the arithmetic total as a check, then apply the rules that actually govern the work.
Use the calculator
Enter each active day, its start and end time, and the unpaid break in minutes. The tool recognizes an end time earlier than the start as a next-day finish and totals the whole week locally in the browser.