How to calculate work hours

Hours and minutes are awkward to subtract directly. Convert each time to minutes since midnight first, then the arithmetic is ordinary subtraction.

9:00 AM  →  9 × 60 + 0   = 540
5:30 PM  → 17 × 60 + 30  = 1050

1050 − 540 = 510 minutes = 8:30 gross

Deduct only break time that is not counted as worked time. Whether a break is paid varies by employer, contract and jurisdiction.

510 − 30 = 480 minutes = 8:00 worked

If the clock-out time is earlier than the clock-in time, add a full day (1440 minutes) to the clock-out before subtracting.

10:00 PM → 1320
6:00 AM  → 360 + 1440 = 1800
1800 − 1320 = 480 minutes = 8:00

Add every day in whole minutes, then divide the total by 60 once. Converting each day first and adding rounded decimals is where payroll discrepancies come from.

437 minutes ÷ 60 = 7.283333… ≈ 7.28 hours

How many hours is 9 to 5:30 with a 30 minute lunch?

8 hours exactly: 8:30 gross minus a 30 minute unpaid break.

Should I round my punches?

Only if your employer's stated practice does. Rounding changes the result, so it should never be applied invisibly.

What about a shift that starts and ends at the same clock time?

Treat it as zero unless it is genuinely a 24-hour shift, in which case mark it as ending the next day.

• Work Hours CalculatorStart and end times with breaks.
• Time Card CalculatorWeekly or biweekly clock punches.
• Decimal Hours CalculatorConvert HH:MM and decimal time.