What Is a Mile?
Definition
Mile: A unit of length used in the United States and the United Kingdom. The international mile is exactly 1,609.344 meters by definition, unlike the nautical mile of 1,852 meters.
The mile is a unit of length used in the United States and the United Kingdom for road distances and speeds. The international mile is 5,280 feet and, since the 1959 international yard and pound agreement, exactly 1,609.344 meters. The nautical mile used at sea and in the air is a separate unit.
Where it appears in the formulas
1 mi = 1,609.344 m and 1 nmi = 1,852 m. The length converter uses these exact factors (NIST SP 811, Appendix B; NIST Handbook 44, Appendix C) and shows the value in every unit.
Nautical mile and US survey mile
The nautical mile (1,852 m) is used at sea and in aviation. The old US survey mile differs very slightly from the international mile; the length converter does not use it.