How to calculate work hours with a lunch break
Convert start and end to minutes past midnight. Subtract. If the result is negative, the shift went past midnight — add 24 hours. Then subtract unpaid lunch. Divide by 60 for decimal hours (what most payroll systems want).
Example: 8:00 AM to 4:00 PM is 8:00. A 60-minute lunch leaves 7:00, or 7.00 decimal hours.
Example: 7:00 AM to 3:00 PM with a 30-minute lunch is 7:30, or 7.50 decimal hours.