Guides / Work hours
How to Calculate Work Hours With Lunch Breaks
A shift from 9:00 AM to 5:30 PM spans 8 hours 30 minutes. If you exclude a 30-minute lunch, the result is 8 hours. The key is to measure the whole shift first, then subtract only the breaks you want excluded.
Step 1: Find the full shift length
Using 24-hour time, convert each clock reading to minutes after midnight. 09:00 is 540 minutes; 17:30 is 1,050 minutes. Subtract: 1,050 − 540 = 510 minutes. That is the elapsed clock-time span before breaks.
Step 2: Add the breaks you intend to deduct
A 30-minute lunch and two excluded 10-minute breaks add up to 50 minutes. Do not deduct a break twice. If you intend to count a paid break as time worked, leave it out of this deduction. The calculator cannot decide which breaks your employer or applicable rules treat as paid.
Step 3: Subtract and convert
For the 510-minute shift with 50 minutes excluded, 510 − 50 = 460 minutes. Divide by 60: seven complete hours use 420 minutes, leaving 40 minutes. The result is 7 hours 40 minutes, or approximately 7.6667 decimal hours.
Net minutes = full shift minutes − excluded break minutes
Compare common examples
| Shift | Break | Net time |
|---|---|---|
| 09:00–17:00 | 30 min | 7h 30m |
| 08:15–16:45 | 45 min | 7h 45m |
| 09:00–17:30 | 50 min | 7h 40m |
From one shift to a week
Calculate each day separately when breaks or shift lengths vary. Four days of 8 hours and one day of 7 hours 40 minutes total 39 hours 40 minutes. Keep the minutes exact until the final conversion; adding rounded daily decimal numbers can introduce small differences.
Use the hours calculator with breaks for one shift or the weekly time card calculator for seven days.
Common mistakes to check
- 7 hours 40 minutes is not 7.40 decimal hours. Divide 40 by 60.
- A break longer than the entire shift is an invalid input.
- For a shift crossing midnight, account for the next day before subtracting breaks.
- These are clock-time calculations. A daylight saving change can alter actual elapsed time.
For another worked example, read how to calculate an overnight shift. Wage, overtime, and break-entitlement decisions require the rules that apply to your situation.