Speed & Velocity Converter
Convert km/h, mph, m/s, knots and Mach.
1 kilometer per hour equals 0.621371 miles per hour
About speed units
Speed is distance divided by time, so every speed unit combines a length unit with a time unit. Road speeds use kilometres per hour or miles per hour, science uses metres per second, and navigation uses knots — one nautical mile per hour, or exactly 1.852 km/h.
Speed combines distance and elapsed time. Knots use the international nautical mile (1852 m), and mph uses the international statute mile (1609.344 m).
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All units
Compare unit values in the base unit. Numbers are rounded to 8 significant digits; conventions and assumptions appear beside the units.
| Unit | Symbol | 1 unit in m/s |
|---|---|---|
| meter per second | m/s | 1 |
| kilometer per hour | km/h | 0.27777778 |
| mile per hour | mph | 0.44704 |
| foot per second | ft/s | 0.3048 |
| knot | kn | 0.51444444 |
| kilometer per second | km/s | 1,000 |
| mile per second | mi/s | 1,609.344 |
| MachMach 1 is not a fixed speed. It tracks the local speed of sound, which falls as air temperature falls, so it is slower at altitude. This converter uses the ICAO Standard Atmosphere value at sea level and 15 °C: 340.29 m/s. | M | 340.29 |
| speed of light | c | 299,792,460 |
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