Stopwatch time to decimal hours converter
Turn a stopwatch reading like 1:23:45.6 into decimal hours, minutes and seconds for timesheets, invoices and time studies, or convert decimal hours back to h:mm:ss.
h:mm:ss → decimal
decimal → h:mm:ss
Why decimal hours?
Payroll and invoicing systems multiply hours by a rate, and that only works with decimals: 1 h 45 min is 1.75 h, not 1.45. To convert, divide minutes by 60 and seconds by 3,600, then add them to the hours. 1:23:45 becomes 1 + 23/60 + 45/3600 = 1.3958 h.
Many firms bill in tenths of an hour (6-minute units), rounded up. The converter shows that too. If you time tasks with the multiple stopwatches, the CSV export includes milliseconds per lap, which you can divide by 3,600,000 in a spreadsheet to get decimal hours.
Minutes to decimal hours
| Minutes | Decimal | Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|---|---|
| 3 | 0.05 | 18 | 0.30 | 33 | 0.55 |
| 6 | 0.10 | 21 | 0.35 | 36 | 0.60 |
| 9 | 0.15 | 24 | 0.40 | 39 | 0.65 |
| 12 | 0.20 | 27 | 0.45 | 42 | 0.70 |
| 15 | 0.25 | 30 | 0.50 | 45 | 0.75 |
Questions people ask
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes = 0.25 h, 20 minutes = 0.33 h, 45 minutes = 0.75 h.
Is 1.5 hours 1 hour 50 minutes?
No. 1.5 hours is 1 hour 30 minutes, because 0.5 × 60 = 30. To go from decimal back to minutes, multiply the decimal part by 60.
How are 6-minute billing units calculated?
Divide total minutes by 6 and round up to a whole unit; each unit is 0.1 h. 32 minutes is 5.33 units, rounded up to 6 units, so 0.6 h.