How to use the speed converter
- Type a value in either box. Decimals with a comma or a point both work.
- Choose the units on each side, or press the arrows to swap them.
- The table below shows the value in every unit at once. Click a row to convert to that unit.
About speed units
Speed is distance over time, so speed units convert with the same factors as distance. A mile is exactly 1.609344 km, so 1 mph is 1.609344 km/h and 100 km/h is 62.1371 mph. Road speeds are in km/h in most countries and in mph in the US and UK.
Science and engineering use meters per second. One m/s is exactly 3.6 km/h, because an hour has 3,600 seconds and a kilometer 1,000 meters, so divide km/h by 3.6 to get m/s.
Ships and aircraft use knots. A knot is one nautical mile (1,852 m) per hour, which is 1.852 km/h or about 1.15078 mph. Weather services give wind speed in km/h, mph, m/s or knots depending on the country.
Popular speed conversions
- Miles per hour to km/h
- Kilometers per hour to mph
- Knots to miles per hour
- Knots to kilometers per hour
- Meters per second to kilometers per hour
- Kilometers per hour to meters per second
- Meters per second to miles per hour
- Miles per hour to meters per second
- Miles per hour to knots
- Kilometers per hour to knots
- Feet per second to miles per hour
- Miles per hour to feet per second
Speed units
| Unit | Symbol | Definition |
|---|---|---|
| Meters per second | m/s | The base unit |
| Kilometers per hour | km/h | 1 km/h = 0.2777777778 m/s |
| Miles per hour | mph | 1 mph = 0.44704 m/s |
| Knots | kn | 1 kn = 0.5144444444 m/s |
| Feet per second | ft/s | 1 ft/s = 0.3048 m/s |
| Kilometers per second | km/s | 1 km/s = 1,000 m/s |
Converting something else? The unit converter covers every kind of unit in one place.