United States customary units
United States customary units form a system of measurement units commonly used in the United States and most U.S. territories, since being standardized and adopted in 1832. The United States customary system developed from English units that were in use in the British Empire before the U.S. became an independent country. 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. Consequently, while many U.S. units are essentially similar to their imperial counterparts, there are noticeable differences between the systems.
A 23.7 US fl oz (700 mL) bottle displaying both U.S. and metric units
The imperial system of units, imperial system or imperial units is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments.
The former Weights and Measures office in Seven Sisters, London (590 Seven Sisters Road)
Imperial standards of length 1876 in Trafalgar Square, London
A baby bottle that measures in three measurement systems—metric, imperial (UK), and US customary
A one US gallon gas can purchased near the US-Canada border showing equivalences in imperial gallons and litres