# Kilometres per hour: Wikis

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More interesting facts on Kilometres per hour

# Encyclopedia

The kilometre per hour (American English: kilometer per hour) is a unit of speed or velocity, expressing the number of kilometers traveled in one hour. The unit symbol is km/h or km·h−1; however, the colloquial abbreviations "kph" and "kmph" are sometimes also used in English-speaking countries, in analogy to mph, although these are not in accordance with international scientific standards. In North American slang and military usage, km/h (as well as km) is commonly pronounced, and sometimes even written, as klicks or kays (K's), although these may also be used to refer to kilometres.

Worldwide, the km/h is the most commonly used speed unit on road signs and car speedometers. Therefore, it is far more common in everyday usage than the proper SI unit of speed, m/s. Along with the kW·h, km/h is the most commonly used metric unit based on the hour, which is only a "non-SI unit accepted for use with the International System of Units" by the BIPM.[1]

## References

1. ^ BIPM brochure (SI reference)
2. ^ 1 yard ≡ 0.9144 m and
1 mile = 1760 yards thus
1 mile = 1760 × 0.9144 ÷ 1000 km

# Simple English

Kilometres per hour is a unit of measurement, which measures speed or velocity. The unit symbol is km/h or km·h−1. By definition, an object travelling at a speed of 1 km/h in a straight line for 1 hour moves 1 kilometre. The unit is the most commonly used unit of speed worldwide, more common than the SI unit of speed, metres per second.

## Conversions

• 3.6 km/h ≡ 1 m/s, the SI unit of speed, metre per second
• 1 km/h ≈ 0.277 78 m/s
• 1 km/h ≈ 0.621 37 mph ≈ 0.911 34 feet per second
• knot ≡ 1.852 km/h (exactly)
• 1 mile = 1.609344 km (~1.61 km)
• n km/h = ( 1.61 * n ) mph (where n is a quantity of speed in km/h)