US Customary Units

United States customary units is a system of measurements used in the United States, which, unlike essentially all other nations, has not widely adopted the SI system. US customary units are primarily used to measure lengths, areas, volumes, weights, temperatures and derived quantities, such as forces and pressures. The United States customary system has its origins in colonial British units, but US customary and British imperial units of the same name often have significant differences due to the 1824 modifications of the British units accompanying the establishment of the (British) imperial system. Confusingly, the term "imperial" is commonly used within the United States to refer to United States customary units. Use Wolfram|Alpha to compare, distinguish and convert between US customary units, British imperial units and units from other systems, including the internationally adopted and nearly universally used SI system of units.