Understanding speed units
A knot is one nautical mile (1,852 meters) per hour. Mach is included as a sea-level approximation at 340.29 m/s; actual sound speed changes with atmospheric conditions.
Conversion method
For linear units, multiply the input by its factor to the base unit, then divide by the target factor. The table lists definitions where exact and approximate constants where applicable.
| Unit | 1 unit in base units | Definition |
|---|---|---|
| Meter per second (m/s) | 1 | Exact definition; display may be rounded |
| Kilometer per hour (km/h) | 0.2777777778 | Exact definition; display may be rounded |
| Mile per hour (mph) | 0.44704 | Exact definition; display may be rounded |
| Foot per second (ft/s) | 0.3048 | Exact definition; display may be rounded |
| Knot (kn) | 0.5144444444 | Exact definition; display may be rounded |
| Mach (sea level) (Ma) | 340.29 | Approximate / conventional value |
Worked example and common conversions
10 km/h = 6.2137119224 mph. Keep full precision during conversion, then round the final result to the precision of your measurement.
| From | To |
|---|---|
| 10 km/h | 6.2137119224 mph |
| 10 mph | 16.09344 km/h |
| 10 m/s | 36 km/h |
| 10 kn | 11.5077944802 mph |
| 10 m/s | 22.3693629205 mph |