United States Customary System
Quick Summary
The United States Customary System is a system of weights and measures derived from the British Imperial System. While the metric system, based on powers of 10, is used by most of the world, the U.S. has largely retained its customary system due to the significant time and financial investment in infrastructure, machinery, and training that occurred during the Industrial Revolution.123
Key characteristics of the U.S. Customary System include:
* Non-decimal conversions: Unlike the metric system, conversions between units are not neatly based on powers of 10. For example, a mile is 5,280 feet, and a gallon is four quarts.4
* Historical roots: Many U.S. units have origins in medieval English standards, with some, like the U.S. gallon and bushel, being smaller than their British counterparts that were adopted later.12
* Joint usage: In modern times, education in the U.S. often includes both the customary system and the metric system, leading to tools like rulers displaying both inches and centimeters.3
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