Kilometres Per Hour - History & Definition

Kilometres per hour is the most commonly seen metric unit of speed, being used for road speed limit signs in most countries in the world. Although technically a derivative unit its usefulness as a term for the speed of motor vehicles has perpetuated its widespread use.

1 km/h = 3.6 m/s (metres per second the formal SI unit of speed)

The unit is formally abbreviated by km/h, however kph and kmph are in common use in both the UK and US and can often be seen on car dashboards.

Some Speed Records in Kilometres Per Hour

• Land Speed Record - Thrust SSC (UK) - 1227.986 kph
• Electric Powered Land Speed Record - Buckeye Bullet (US) - 517.942 kph
• Motorcylce Land Speed Record - Top Oil Ack Attack (US) - 605.697 kph
• Rail Speed Record - SNCF TGV POS (F) - 574.80 kph
• Maglev Speed Record - JR-Maglev MLX01 (J) - 581.00 kph
• Water Speed Record - Spirit of Australia (AUS) - 511.13 kph

See our miles per hour page for the speed records in mph