Convert kmh to mph

One kilometer per hour equals 0.621371 miles per hour. To convert any number of kilometers per hour to miles per hour, multiply by 0.62137119.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Speed conversions divide by audience. Road speeds move between kilometres and miles per hour and are what a driver or a runner needs. Metres per second is what every equation of motion expects, so it is the form any physics problem has to reach. Knots belong to the sea and the air, where one knot is one nautical mile per hour and a nautical mile is one minute of latitude — a system built around navigation rather than around convenience.

kmh to mph formula

To go the other way, use kilometer per hour = mile per hour ÷ 0.62137119.

About these units

Kilometres per hour is the road-speed unit in most of the world. Dividing by 3.6 converts it to metres per second, the SI unit physics uses.

Miles per hour remains the road-speed unit in the United States and the United Kingdom, which is why British road signs are in miles while everything else on them is metric.

Kilometer per hour is also written kilometres per hour, kmh, kph, kmph, km/hr and kmh. Mile per hour is also written miles per hour and mi/h.

Sources

1. National Bureau of Standards, "Refinement of Values for the Yard and the Pound", Federal Register, 1 July 1959 — the international yard as exactly 0.9144 m and the avoirdupois pound as exactly 0.45359237 kg.