The short ton is a unit of weight equal to 2,000 pounds (907.18474 kg).^[1] In the United States it is often called simply ton^[1] without distinguishing it from the metric ton (tonne, 1,000 kilograms) or the long ton (2,240 pounds/1,016.0469088 kilograms); rather, the other two are specifically noted. There are, however, some U.S. applications for which unspecified tons normally means long tons (for example, Navy ships)^[2] or metric tons (world grain production figures).

Both the long and short ton are defined as 20 hundredweights, but a hundredweight is 112 pounds (50.80234544 kg) in the Imperial system (long or gross hundredweight) and 100 pounds (45.359237 kg) in the U.S. system (short or net hundredweight).^[1]

The spelling tonne is from Gallic and French. The term applied to the barrel of the largest size. In Old English the spelling was tunne, "cask". A full cask about 1 metre (39.4 in) high could easily weigh a metric tonne, since the volume of the antiquated British wine cask tun is defined as 954 litres (210 imp gal; 252 US gal) which for water (density = 1 g/cm³) amounts to as many kilograms.

A short ton–force is 2,000 pounds-force (8,896.443230521 N).

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