Field guide
Why 7 hours 30 minutes is 7.5 hours, not 7.30
Why 7 hours 30 minutes is 7.5 hours, not 7.30. A practical guide to base-60 minutes, decimal hours, and display rounding for U.S. timecards.
Reviewed 2026-09-12 · Shift Ledger
Minutes are sixtieths of an hour
Divide remaining minutes by 60 before adding them to whole hours. Thirty minutes is 30 ÷ 60 = 0.5 hour. So 7 hours 30 minutes is 7.5 hours.
Reverse the calculation
The digits after a decimal point are fractions of an hour. 7.30 hours × 60 = 438 minutes, which is 7 hours 18 minutes. It does not represent 7 hours 30 minutes.
Use these reference values
15 minutes = 0.25 hour; 30 minutes = 0.50 hour; 45 minutes = 0.75 hour. One minute is approximately 0.016667 hour. The converter rounds displayed decimal hours to two places and reverse conversions to the nearest minute.
Total exact minutes first
Three 20-minute periods total 60 minutes, or 1.00 hour. Adding three two-place displays of 0.33 would give 0.99 instead. Timecards here add whole minutes first and format the final total.
Keep clock time and duration separate
8:30 AM is a point on a clock. A duration of 8 hours 30 minutes is 8.5 hours. Use the work-hours calculator to find a duration between clock times, then convert that duration if needed.
Frequently asked questions
Why is 30 minutes not 0.30 hours?
Because minutes are base-60, not base-100. 30 minutes is 30/60 = 0.5 hours. 0.30 hours would be only 18 minutes.
How do I convert 8.75 hours to hours and minutes?
Multiply 0.75 by 60 = 45 minutes. So 8.75 hours = 8 hours 45 minutes.
Should I round decimal hours on my timecard?
Keep exact minutes for totals. Round only the final weekly total to two decimal places for display. Adding individually rounded decimals can introduce small errors.
Open the Decimal Hours Converter →
Open the printable decimal-hours chart
Found an issue? Contact the maintainer with the example and expected result. Please omit personal timecards.