|Full name(s)||Common name||Quantity||Notes|
|long ton, weight ton, gross ton||"ton" (UK)||2,240 lb (1,016.047 kg)||Used in countries such as the United Kingdom that formerly used the Imperial system|
|short ton, net ton||"ton" (US)||2,000 lb (907.1847 kg)||Used in North America|
|tonne||"metric ton" (mainly US)||1,000 kg (2,204.623 lb)||Defined in the International System of Units. In the UK, Canada, Australia, and other areas that had used the Imperial system, the tonne is the form of ton legal in trade. Less than 2% different from the long ton.|
|ton shortweight||2240 lb||Used in the iron industry in the 17th and 18th centuries.|
|ton longweight||2400 lb||Used in the iron industry in the 17th and 18th centuries.|
The tonne (unit symbol t) or metric ton (U.S.), often written pleonastically as metric tonne, is a unit of mass equal to 1,000 kg (2,204.62 lb) (103 kilograms) which is almost exactly the mass of one cubic metre of water at four degrees Celsius. It is sometimes abbreviated to mt in the United States, although this conflicts with other SI symbols.