Math & Everyday
Hours Calculator
Enter a start time, end time, and unpaid break to get your hours per day in both hours-and-minutes and decimal form, plus weekly and monthly totals. Overnight shifts are handled automatically.
Quick answer: Hours worked = end time minus start time, minus unpaid breaks. A 9:00 am to 5:30 pm day with a 30-minute lunch is 8 hours — 40 hours across a five-day week.
Counts the time from start to end (adding 24 hours when the end time is earlier, for overnight shifts), then subtracts the unpaid break. Weekly hours multiply by days worked; monthly hours use the average month (weekly × 52 ÷ 12).
How it works
1. Enter your start and end times
Set when the shift starts and ends. If the end time is earlier than the start, the calculator assumes the shift crosses midnight and adds 24 hours — so 10 pm to 6 am counts as 8 hours.
2. Subtract unpaid breaks
Enter unpaid break minutes to deduct them from the total. A 60-minute lunch turns a 9-to-5 into 7 paid hours.
3. Scale to a week and month
Set your days per week to see weekly hours, and a monthly figure computed as the weekly total × 52 weeks ÷ 12 months — the convention payroll systems use.
Frequently asked questions
How do I convert minutes to decimal hours?
Divide the minutes by 60. Thirty minutes is 0.5 hours, 45 minutes is 0.75, and 20 minutes is 0.33. Payroll systems use decimal hours, which is why 8 h 30 m appears as 8.5 on a timesheet.
How does an overnight shift count?
When the end time is earlier than the start time, the shift crosses midnight, so 24 hours are added. A 10:00 pm to 6:00 am shift is 8 hours before breaks.
How many work hours are in a month?
A 40-hour week works out to about 173 hours a month (40 × 52 ÷ 12). Actual calendar months range from about 160 to 184 scheduled hours depending on how the weeks fall.