Mile Per Hour (mph)

US & ImperialCurrent unit

Exactly 0.44704 m/s. The unit for road speeds in the US, UK and a few other countries.

1 mile per hour = 0.44704 meters per second (exactly).

About the mile per hour

Early British motoring law is the best window into this unit. The 1861 Locomotive Act set a limit of 10 mph for light locomotives. The 1865 Red Flag Act cut it to 4 mph in the country and 2 mph in towns, with a person walking ahead with a flag. The Locomotives on Highways Act of 1896 raised it to 14 mph, and the Motor Car Act of 1903 to 20 mph. In 1931 all limits for cars were abolished, and 30 mph in built-up areas returned in 1935.

The mile per hour combines the mile, set at 5,280 feet in Elizabeth I's reign, with the hour, and it equals exactly 0.44704 m/s or 1.609344 km/h. The United Kingdom and United States use it on roads, along with several smaller countries, mostly territories or former territories of those two, and the US, Canada and Ireland use it for rail. Sports such as cricket, tennis and baseball quote ball speeds in it. Aviation and shipping prefer knots, about 0.869 of one mph each.

Sources: Wikipedia: Miles per hour; Wikipedia: Speed limits in the United Kingdom; Wikipedia: Mile

Mile Per Hour conversion chart

1 mile per hour expressed in every other speed unit:

More US & Imperial units

• foot per second (speed)
• inch per second (speed)
• foot per minute (speed)
• mile per second (speed)
• inch (length)
• foot (length)
• yard (length)
• mile (length)
• thou (length)
• league (length)
• furlong (length)
• chain (length)
• rod (length)
• link (length)
• hand (length)
• pound (weight & mass)

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