The short ton (symbol tn) is a measurement unit equal to 2,000 pounds (907.18 kg). It is commonly used in the United States, where it is known simply as a ton, although the term is ambiguous, the single word being variously used for short, long, and metric ton.
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).
In the United States, a short ton is usually known simply as a "ton", without distinguishing it from the tonne (1,000 kilograms or 2,204.62 pounds), known there as the "metric ton", or the long ton also known as the "imperial ton" (2,240 pounds or 1,016.05 kilograms). 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 pounds (45.36 kg) in the US system (short or net hundredweight) and 112 pounds (50.80 kg) in the imperial system (long or gross hundredweight).
"NIST Handbook 44 Specifications: Handbook 44 – 2013 Appendix C – General Tables of Units of Measurement" (PDF). April 26, 2006. p. C-6. Retrieved October 13, 2008.
20 hundredweights = 1 ton
- Butcher, Crown and Gentry, NIST Special Publication 1038, The International System of Units (SI) – Conversion Factors for General Use, 2006
- "Naval Architecture for All". United States Bureau of Transportation Statistics. Retrieved October 13, 2008.