Mile (mi)
Definition
The mile (symbol mi) is an imperial and US customary unit of length equal to exactly 1,609.344 meters. The international mile is divided into 5,280 feet or 1,760 yards and is the standard road-distance unit in the United States and the United Kingdom.
History
The mile descends from the Roman mille passus, a thousand paces of about 1,479 meters. Medieval England adopted a longer version anchored to the furlong; Elizabeth I's statute of 1593 fixed the statute mile at 8 furlongs, or 5,280 feet.
Imperial standardization in 1824 confirmed the statute mile, and the 1959 international yard and pound agreement aligned the US and UK definitions by tying the yard to exactly 0.9144 meters. That choice fixed the international mile at exactly 1,609.344 meters and retired the slightly different US survey mile, which lingered for geodesy until the US survey foot was officially deprecated on 1 January 2023.
Standard reference
Defined under the 1959 international yard and pound agreement as 1,760 × 0.9144 m = 1,609.344 m exactly. NIST Special Publication 811 lists this as the conversion factor used by U.S. legal metrology.
Common conversions
| 1 mi | = 1,609.344 m |
|---|---|
| = 1.609344 km | |
| = 5,280 ft | |
| = 1,760 yd |