Kilometres per hour

Speed limit in km/h on a road in Denmark.

The kilometre per hour or kilometer per hour (symbol: km/h, km h^-1 or km·h⁻¹) is a unit of speed or velocity.

Definition

Speed limit units on traffic signs around the world:      Kilometers per hour (km/h)     Miles per hour (mph)     Both     No speed limit units

By definition, an object travelling at a speed of 1 km/h in a straight line for one hour moves one kilometre. The unit is the most commonly used unit of speed worldwide, more common than the SI unit of speed, metre per second (m/s or m s^-1).

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
• 1 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)
• 1 mph = ~1.6 km/h

Kilometres Per Hour Media

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  Speed limit sign in the Republic of Ireland, using "km/h."

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  100 km/h sign following the most common implementation of the Vienna Convention style (Hungary)

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  Swedish 30 km/h speed limit – the yellow background provides a contrast in case snow covers the background against which one perceives the road sign.

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  Since the text "km/h" on this Irish speed limit sign is a symbol, not an abbreviation, it represents both "kilometres per hour" (English) and "ciliméadar san uaircode: ga is deprecated " (Irish)

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  60 km/h speed limit in Arabic numerals (below) and Arabic script (above) (UAE)

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  Waterways speed limit of 9 km/h (Finland)

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  Samoa uses both miles per hour and kilometres per hour

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  50 km/h sign in Mexico

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  Advisory 40 km/h sign in Norway

Related pages

• Kinematics