# Kilometres per hour

**km/h** is a

unit of

speed, read "kilometres per

hour." An object travelling at a speed of 1 km/h would move 1 kilometre in one hour if the speed remained constant for that hour.

This unit is sometimes written **kph**, although in general this is casual rather than rigorous usage.

## Examples of speeds in km/h

5 km/h | Walking speed |

20 km/h | Easy bicycling speed |

50 km/h | Residential speed limit |

80-90 km/h | Speed limit on a major road |

110-120 km/h | Highway speed |

300 km/h | High-speed railroad |

1000 km/h | Airliner cruising speed |

40,320 km/h | Earth's escape velocity |