The short ton (abbreviation tn ) is a measurement unit equal to 2,000 lb. It is commonly used in the United States, where it is known simply as a ton; however, the term is ambiguous, the single word "ton" being variously used for short, long, and metric tons. The various tons are defined as units of mass. They are sometimes used as units of weight, the force exerted by a mass at standard gravity (e.g., short ton-force). One short ton exerts a weight at one standard gravity of 2,000 pound-force (lbf).

United States

In the United States, a short ton is usually known simply as a "ton", without distinguishing it from the tonne (1000 kg), known there as the "metric ton", or the long ton also known as the "imperial ton" (2240 lb). There are, however, some U.S. applications where unspecified tons normally mean long tons (for example, naval ships) or metric tons (world grain production figures). Both the long and short ton are defined as 20 hundredweights, but a hundredweight is 100 lb in the US system (short or net hundredweight) and 112 lb in the imperial system (long or gross hundredweight). A short ton–force is 2000 lb-f.