In 1789, Thomas Jefferson, then the U.S. secretary of state, developed a system of measures quite similar to what would become the metric system. Congress, however, never adopted it into law as the nation's only system of measurement.
According to the U.S. Metric Association, the Metric Conversion Act (passed in 1975; amended in 1988) states that the metric system is the nation's preferred measurement system and that the government encourages its use.
Despite the metric system's simplicity and widespread use around the world, U.S. consumers have resisted a wholesale conversion away from the foot, mile, pound and other non-metric measurements.
In keeping with consumers' preference for familiar measurements, most consumer products created today are labeled with the non-metric measurement followed by the metric measurement in parentheses.
In certain lines of work in the U.S., the use of metric measurements is standard. The fields of science, engineering, manufacturing and international trade depend almost entirely on the metric system.