A mile is a unit of length, usually used to measure distance, in a number of different systems. In contemporary English contexts, mile most commonly refers to the statute mile of 5,280 feet (exactly 1,609.344 meters) or the nautical mile of 1,852 meters (about 6,076.1 ft). There are many other historical miles, and similar units in other systems translated as miles in English, varying between one and fifteen kilometers. It is about a third of the old measurement, a League.

The measurement is now used almost exclusively in the United States, Britain, Liberia and Myanmar. It has been replaced by the kilometre as a measure of distance elsewhere. It is sometimes retained as a customary unit.

There have been several abbreviations for mile (with and without trailing period): mi, ml, m, M. In the United States, the National Institute of Standards and Technology now uses and recommends mi but in everyday usage (at least in the United States and in the United Kingdom) usages such as miles per hour and miles per gallon are almost always abbreviated as mph or mpg (rather than mi/h or mi/gal).

The formula "multiply by 8 and divide by 5" to convert international miles to kilometers gives a conversion of 1.6, which, at less than 1% high, makes a useful approximation.

Statute mile

The statute mile is the distance typically meant when the word mile is used without other qualifying words, though in nautical, aviation, and polar exploration the nautical mile might be used without qualification.

The current definition of a mile as 5,280 feet (as opposed to 5,000) dates to the 13th century, and was confirmed by statute in the reign of Queen Elizabeth I; However, various English-speaking countries maintained independent length standards for the yard, which differed by small but measurable amounts, and thus led to miles of slightly different lengths. This was resolved in 1959 with the definition of the current international mile by Australia, Canada, New Zealand, South Africa, the United Kingdom, and the United States.

The international mile being 5,280 feet is defined in terms of the international foot (0.3048 m), while the statute miles of the various English-speaking countries were based on the national foot of each country.

The name statute mile originates from a statute of the Parliament of England in 1592 during the reign of Elizabeth I. This defined the statute mile as 5,280 ft or 1,760 yards; or 63,360 inches. Both statute and international miles are divided into eight furlongs. In turn a furlong is ten chains; a chain is 22 yards and a yard is three feet, making up 5,280 ft.

A national statute mile still in limited use is the U.S. survey mile of 5,280 survey feet which is slightly longer at approximately 1,609.347219 meters (1 international mile is exactly 0.999998 survey mile). Thompson and Taylor of the National Institute of Standards and Technology give many unit conversion factors, but for statute mile, only state "8 fur = 1 U.S. survey mile (also called 'statute mile') = 1 mi = 5280 ft" (in that section, abbreviations in italic type indicates the U.S. survey foot or U.S. survey mile). Nowhere in that publication is the name "statute mile" applied to the international mile.