How do I calculate hours from a start and end time?

Convert both clock times to elapsed time, then subtract any unpaid break. For a same-day shift, end time minus start time gives the basic duration.

How do I calculate an overnight shift?

Treat the end time as occurring on the next day. A 10:00 PM to 6:00 AM shift is 8 hours before subtracting breaks.

How do I convert minutes to decimal hours?

Divide the minutes by 60. For example, 30 minutes divided by 60 equals 0.50 hours.

Work hours guide

How to Calculate Work Hours

A practical way to turn clock-in and clock-out times into paid hours, including breaks, overnight shifts, split shifts, and decimal-hour conversions.

1. Start with clock-in and clock-out time

For a shift that starts and ends on the same day, subtract the start time from the end time. An 8:00 AM to 4:30 PM shift lasts 8 hours 30 minutes before breaks. If mental subtraction is awkward, convert the clock times to minutes after midnight. 8:00 AM is 480 minutes and 4:30 PM is 990 minutes. The difference is 510 minutes, or 8 hours 30 minutes.

Example:4:30 PM − 8:00 AM = 8h 30m

2. Subtract unpaid breaks

Only subtract break time that is actually unpaid. If the 8:00 AM to 4:30 PM shift includes a 30-minute unpaid lunch, subtract 30 minutes from the 8-hour-30-minute shift. That leaves 8 paid hours. If a break is paid under the rules or policy that applies to you, it stays inside paid time rather than being deducted.

Example:8h 30m − 30m lunch = 8h paid

For a one-off shift, the Break & Lunch Calculator does this directly. For an entire week, use the Time Card Calculator.

3. Handle overnight shifts as next-day time

An overnight shift can look negative if you subtract the clock times without accounting for midnight. Treat the end time as occurring on the following day. A shift from 10:00 PM to 6:00 AM spans 2 hours before midnight plus 6 hours after midnight, for a total of 8 hours. A 30-minute unpaid break would reduce that to 7 hours 30 minutes of paid time.

Example:10:00 PM → 6:00 AM = 8h; minus 30m = 7h 30m

4. Add split shifts separately

If you work more than one block in the same day, calculate each block and add them together. For example, 8:00 AM to noon is 4 hours, and 2:00 PM to 6:00 PM is another 4 hours. The day total is 8 hours. Treating the whole span as 8:00 AM to 6:00 PM would incorrectly count the two-hour gap as work time. The Work Hours Now time card lets you add up to three work blocks per day for this reason.

5. Convert minutes to decimal hours when needed

Payroll systems often use decimal hours. To convert minutes to a decimal, divide the minutes by 60. Fifteen minutes is 0.25 hours, 30 minutes is 0.50, and 45 minutes is 0.75. Do not treat clock minutes as hundredths: 7 hours 30 minutes is 7.50 hours, not 7.30. For quick reference, use the Decimal Hours Conversion Chart or the Decimal Hours Calculator.

6. Total the week before applying a weekly overtime rule

Once each day's paid time is correct, add the days to get the weekly total. If you are estimating overtime, apply the threshold and multiplier that are appropriate for your situation. A common example is 1.5× the base wage for hours above 40 in a workweek, but overtime eligibility and rules vary. Work Hours Now keeps the threshold and multiplier editable rather than assuming one legal rule applies to everyone.

A faster way: use the calculator

The arithmetic is simple once each step is separated, but repeating it across seven or fourteen days creates opportunities for mistakes. The Time Card Calculator handles same-day shifts, overnight shifts, multiple work blocks, unpaid breaks, weekly overtime, and estimated gross pay in one place. If you only need a record to print, use the Printable Timesheet Template.