Long Ton (long tn)
The long ton (also called the imperial ton or displacement ton) is a unit of mass equal to 2,240 pounds or approximately 1,016 kilograms. It was the traditional ton of the British Empire and remains in limited use in British shipping and for certain commodities. The long ton is about 1.6% heavier than the metric ton and 12% heavier than the US short ton.
Definition
One long ton equals exactly 2,240 avoirdupois pounds, 20 long hundredweights of 112 pounds each, approximately 1,016.047 kilograms, approximately 1.01605 metric tons, or approximately 1.12 short tons. The long ton is slightly larger than the metric ton and substantially larger than the US short ton.
History
The long ton derives from the medieval English system in which one ton equalled 20 hundredweights of 112 pounds each, totalling 2,240 pounds. This definition was standard across the British Empire for centuries. As American commerce developed, the United States simplified the hundredweight to 100 pounds, creating the 2,000-pound short ton. The coexistence of two different "tons" caused persistent confusion in transatlantic trade. During the 20th century, most of the world adopted the metric ton (1,000 kg) for international commerce, and the UK itself shifted to metric units for trade in 1985, relegating the long ton to niche applications.
Common Uses
The long ton survives primarily in British shipping, where displacement tonnage of older vessels may still reference it. Some British commodity trades, particularly in metals and coal, historically used the long ton, though metric tons have largely replaced it. Naval architecture sometimes references the long ton for displacement calculations of warships. The long ton has no significant use outside of British and Commonwealth contexts and is increasingly rare even there. In everyday life, the long ton has been entirely superseded by the metric ton in the UK.
Did You Know? Facts About Long Ton
- HMS Victory, Nelson's flagship at Trafalgar, had a displacement of about 3,500 long tons - modern aircraft carriers displace over 100,000 long tons.
- The long ton is almost exactly one metric ton - the difference is only about 1.6%, which is close enough to cause dangerous confusion in cargo loading.
- The phrase "a ton of bricks" traditionally referred to a long ton in British English - 2,240 pounds of bricks.
- The long ton is still occasionally used in the British scrap metal trade, though metric pricing is now standard.
- Three different "tons" exist: the short ton (2,000 lbs), the long ton (2,240 lbs), and the metric ton (2,204.6 lbs) - none of which are equal.