Common speed conversions
| From | To | Multiply by |
|---|---|---|
| km/h | mph | 0.621371 |
| mph | km/h | 1.609344 |
| m/s | km/h | 3.6 |
| km/h | m/s | 0.277778 |
| Knots | km/h | 1.852 |
Why m/s to km/h is × 3.6
One metre per second means 3,600 metres in an hour (60 × 60 seconds), and 3,600 metres is 3.6 km. So multiply m/s by 3.6 to get km/h, and divide km/h by 3.6 to get m/s. Physics questions usually want answers in m/s, so this is the conversion students need most.
Everyday speeds
| What | km/h | mph |
|---|---|---|
| Walking | 5 | 3.1 |
| City speed limit | 50 | 31 |
| Motorway limit in Pakistan | 120 | 75 |
| Fast cricket delivery | 150 | 93 |
Knots (nautical miles per hour) are used for ships, aircraft and wind speed. Mach 1 is the speed of sound, which changes with air temperature; the converter uses 340.29 m/s, its value at sea level at 15 °C.