km/h

kilometer per hour

Speedexact by definition

The kilometre per hour is exactly 1,000/3,600 of a metre per second, that is 1/3.6 m/s. The relation is exact by definition, though the decimal 0.2777... repeats and must be truncated when written. It is the standard road speed unit in most of the world.

Watch out: Divide by 3.6 to reach m/s and multiply by 3.6 to come back. The 100 km/h motorway limit is 27.8 m/s, and 62 mph.

1 km/h 0.27777778 m/s