How to Add and Subtract Hours and Minutes

Convert minutes to decimal hours before copying durations into a decimal timesheet.

Use the Time Calculator alongside this illustrative example.

A practical example

Seven hours and forty-five minutes is 7 + 45/60 = 7.75 hours. Adding a second interval of two hours thirty minutes gives ten hours fifteen minutes, or 10.25 decimal hours. Writing 7.45 treats the minutes as hundredths of an hour and understates the first interval.

Check the result

Keep hours, minutes and seconds in the fields intended for them. Compare the total with a rough estimate and check whether your payroll or logging system expects a duration, a clock time or decimal hours.

Try a comparison

Subtract a fifteen-minute break from eight hours. The duration becomes seven hours forty-five minutes, or 7.75 decimal hours. Whether that break is unpaid is a policy question; the subtraction only shows the arithmetic if it should be excluded.

What this does not establish

The arithmetic does not determine paid breaks or billable time. Apply the agreed timesheet rules separately.

Report unclear guidance or a result that needs checking.