Seconds come in sixties, which makes adding and averaging a column of readings tedious. A decimal-minute stopwatch divides the minute into 100 parts instead, so 0.35 min plus 0.47 min is simply 0.82 min. Decimal-hour watches divide the hour into 10,000 parts, which suits work measured against hourly rates.
Conversion table
| Decimal minutes | Seconds | Decimal hours | TMU |
|---|---|---|---|
| 0.01 min | 0.6 s | 0.00017 h | 17 |
| 0.05 min | 3 s | 0.00083 h | 83 |
| 0.1 min | 6 s | 0.00167 h | 167 |
| 0.25 min | 15 s | 0.00417 h | 417 |
| 0.5 min | 30 s | 0.00833 h | 833 |
| 0.75 min | 45 s | 0.01250 h | 1,250 |
| 1 min | 60 s | 0.01667 h | 1,667 |
| 1.5 min | 90 s | 0.02500 h | 2,500 |
| 2 min | 120 s | 0.03333 h | 3,333 |
| 5 min | 300 s | 0.08333 h | 8,333 |
| 10 min | 600 s | 0.16667 h | 16,667 |
- Decimal minutes to seconds: multiply by 60.
- Seconds to decimal minutes: divide by 60.
- Decimal hours to minutes: multiply by 60.
- TMU to seconds: multiply by 0.036. One minute is about 1,667 TMU.
What a TMU is
A time measurement unit is one hundred-thousandth of an hour (0.00001 h, or 0.036 seconds). It's the unit used by predetermined motion time systems such as MTM, where basic motions — reach, grasp, move, position — have tabulated times in TMU.
To time a job in any of these units, use the time study stopwatch, or switch the main stopwatch's display units.