Speed converter
Convert between any two of 6 speed units. Conversion runs in your browser.
More detailsUnits covered · Everyday speed conversions · The units and where each is used · Mach is not a fixed speed
Units covered
| Unit | Symbol | In meter per seconds |
|---|---|---|
| Meter per second | m/s | 1 |
| Kilometer per hour | km/h | 0.2777778 |
| Mile per hour | mph | 0.44704 |
| Knot | kn | 0.5144444 |
| Foot per second | ft/s | 0.3048 |
| Mach | M | 340.29 |
Everyday speed conversions
| 1 of these | m/s | km/h | mph | kn |
|---|---|---|---|---|
| Meter per second | 1 | 3.6 | 2.236936 | 1.943844 |
| Kilometer per hour | 0.2777778 | 1 | 0.6213712 | 0.5399568 |
| Mile per hour | 0.44704 | 1.609344 | 1 | 0.8689762 |
| Knot | 0.5144444 | 1.852 | 1.150779 | 1 |
Each row is one of that unit, given in each of the others.
The units and where each is used
Road speeds are kilometres or miles per hour, air and sea speeds are knots, and physics is metres per second. A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 m — chosen because it is one minute of latitude, which makes navigation arithmetic on a chart trivial. That is why aviation and shipping kept it while everything else moved on.
Mach is not a fixed speed
Mach 1 is the local speed of sound, which depends on air temperature and therefore on altitude. It is about 1,225 km/h at sea level on a standard day and around 1,062 km/h in the stratosphere, where airliners cruise. The figure used here is the sea-level standard, so treat a Mach conversion as an approximation unless you know the conditions.