mile

The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of length; both are based on the older English unit of length equal to 5,280 English feet, or 1,760 yards. The statute mile was standardised as a unit of length between the Commonwealth of Nations and the United States by an international agreement in 1959, when the yard was formally redefined with respect to SI units as 0.9144metres, making the mile exactly (). For everyday use, five miles equates roughly to eight kilometres. Mileage is the term used informally for a distance expressed in miles.

With qualifiers, mile is also used to describe or translate a wide range of units derived from or roughly equivalent to the Roman mile (roughly ), such as the nautical mile (now exactly), the Italian mile (roughly ), and the Chinese mile (now exactly). The Romans divided their mile into 5,000 (), but the greater importance of furlongs in the Elizabethan-era England meant that the statute mile was made equivalent to or in 1593. This form of the mile then spread across the British Empire, some successor states of which continue to employ the mile. The US Geological Survey now employs the metre for official purposes, but legacy data from its 1927 geodetic datum has meant that a separate US survey mile continues to see some use, although it was officially phased out in 2022. While most countries replaced the mile with the kilometre when switching to the International System of Units (SI), the international mile continues to be used in some countries, such as the United Kingdom, the United States, and a number of countries with fewer than one million inhabitants, most of which are UK or US territories or have close historical ties with the UK or US.