Units
Speed converter
Kilometres per hour to miles per hour, metres per second and knots. For driving abroad, for physics and for sailing.
Conversions are worked out on your own machine. No sign-up, no waiting and nothing sent anywhere.
Common conversions
| kilometre per hour | mile per hour |
|---|---|
| 10 km/h | 6.2137 mph |
| 30 km/h | 18.641 mph |
| 50 km/h | 31.069 mph |
| 80 km/h | 49.71 mph |
| 100 km/h | 62.137 mph |
| 120 km/h | 74.565 mph |
| 200 km/h | 124.274 mph |
| mile per hour | kilometre per hour |
|---|---|
| 10 mph | 16.093 km/h |
| 30 mph | 48.28 km/h |
| 50 mph | 80.467 km/h |
| 80 mph | 128.748 km/h |
| 100 mph | 160.934 km/h |
| 120 mph | 193.121 km/h |
| 200 mph | 321.869 km/h |
| metre per second | kilometre per hour |
|---|---|
| 10 m/s | 36 km/h |
| 30 m/s | 108 km/h |
| 50 m/s | 180 km/h |
| 80 m/s | 288 km/h |
| 100 m/s | 360 km/h |
| 120 m/s | 432 km/h |
| 200 m/s | 720 km/h |
| knot | kilometre per hour |
|---|---|
| 10 kn | 18.52 km/h |
| 30 kn | 55.56 km/h |
| 50 kn | 92.6 km/h |
| 80 kn | 148.16 km/h |
| 100 kn | 185.2 km/h |
| 120 kn | 222.24 km/h |
| 200 kn | 370.4 km/h |
Worked out with the same factors the converter above uses.
The most-searched conversion is km/h to mph, and it nearly always comes from driving in a country that signs in the other one. The factor is exactly 1.609344: a 60 mph limit is 96.6 km/h and a 70 mph limit is 112.7 km/h. As a mental shortcut, multiply by 1.6 — or halve and add 60%.
In physics the SI unit is the metre per second, and its relationship to km/h is convenient: divide by 3.6. 36 km/h is exactly 10 m/s. Worth remembering, because almost every kinematics formula expects m/s and feeding it km/h is a classic source of nonsense answers.
The knot is one nautical mile per hour, exactly 1.852 km/h, used in shipping and aviation for the same reason as the nautical mile: it matches the chart. Mach, by contrast, is not a fixed unit: it is speed relative to sound, which depends on air temperature. The value here assumes sea level at 15 °C, which is why it is flagged as approximate.
Every unit in this category
Frequently asked questions
How many km/h is 60 mph?
96.56 km/h. And 70 mph is 112.65 km/h. The exact factor is 1.609344.
How do I convert km/h to m/s quickly?
Divide by 3.6. 90 km/h is 25 m/s. It is the conversion to do before putting a speed into almost any physics formula.
Why isn't mach a fixed number?
Because mach 1 is the speed of sound, and that changes with air temperature: at sea level it is about 1,225 km/h, but at 11,000 metres it drops to roughly 1,062. The value on this page assumes sea level at 15 °C.