Įxecutive Order 12770, signed by President George H. According to the CIA World Factbook, the United States is one of three nations (along with Liberia and Myanmar (Burma)) that have not adopted the metric system as their official system of weights and measures. labeling requirements on food products, where SI units are almost always presented alongside customary units. The legislation states that the federal government has a responsibility to assist industry as it voluntarily converts to the metric system, i.e., metrification. government passed the Metric Conversion Act of 1975, which made the metric system 'the preferred system of weights and measures for U.S. His organization later went so far as to publish music for a song proclaiming 'down with every 'metric' scheme'. The president of an Ohio auxiliary of the Institute wrote that the traditional units were 'a just weight and a just measure, which alone are acceptable to the Lord'. Some advocates of the customary system saw the French Revolutionary, or metric, system as atheistic. The customary system was championed by the U.S.-based International Institute for Preserving and Perfecting Weights and Measures in the late 19th century. Both systems are derived from English units, a system which had evolved over the millennia before American independence, and which had its roots in both Roman and Anglo-Saxon units. The United States system of units of 1832 is based on the system in use in Britain prior to the introduction to the British imperial system on January 1, 1826. See also: Imperial and US customary measurement systems and Comparison of the imperial and US customary measurement systems

For newer types of measurement where there is no traditional customary unit, international units are used, sometimes mixed with customary units: for example, electrical resistance of wire expressed in ohms (SI) per thousand feet. National Institute of Standards and Technology (NIST). The International System of Units (SI), the modern form of the metric system, is preferred for many uses by the U.S. In science, medicine, many sectors of industry, and some government and military areas, metric units are used. The United States uses customary units in commercial activities, as well as for personal and social use. These definitions were refined by the international yard and pound agreement of 1959. customary units were redefined in terms of the meter and kilogram with the Mendenhall Order of 1893 and, in practice, for many years before. units are essentially similar to their imperial counterparts, there are significant differences between the systems.

The United Kingdom's system of measures was overhauled in 1824 to create the imperial system, which was officially adopted in 1826, changing the definitions of some of its units. The United States customary system developed from English units that were in use in the British Empire before the U.S. territories, since being standardized and adopted in 1832. United States customary units form a system of measurement units commonly used in the United States and most U.S. Countries using the metric ( SI), imperial, and US customary systems as of 2019

112 cups to gallons