Convert femtometer to mile (US survey) Online | Free Length Converter

Femtometer

A femtometer (fm) is a unit of length in the metric system, equal to one-quadrillionth of a meter (1 fm = 10⁻¹⁵ meters). It is also known as a fermi, named after the physicist Enrico Fermi. Femtometers are used to measure extremely small distances at the subatomic level, such as the size of protons, neutrons, and atomic nuclei. For example, the radius of a proton is about 0.84 femtometers. This unit is commonly used in nuclear physics and particle physics, but it's far too small for everyday measurements.

Mile (US Survey)

The US survey mile is a unit of length used in land surveying in the United States. It is defined as exactly 5,280 survey feet, with one survey foot equal to 1200/3937 meters (approximately 0.3048006096 meters). This makes the US survey mile equal to about 1,609.3472 meters, slightly longer than the international (statute) mile, which is exactly 1,609.344 meters.

The US survey mile was established to maintain consistency with older land measurement systems based on the Mendenhall Order of 1893. It was commonly used in mapping, legal land descriptions, and public land surveys.

Although the difference between the survey and statute mile is very small (about 3.2 millimeters), it can be significant over large distances. As of 2023, the U.S. has officially retired the survey foot (and survey mile) for most applications, favoring the international foot and mile to standardize measurements.