long ton
{{Short description|Unit of mass}}
{{Infobox unit
| image =
| caption =
| standard = Imperial units, United States customary units
| quantity = Mass
| symbol = long ton
| symbol2 =
| extralabel = In base units
| extradata = {{convert|1.000|LT|lb|disp=out}}
| units1 = SI base units
| inunits1 = {{convert|1|LT|kg|sigfig=7|disp=out}}
| units2 = Metric tons
| inunits2 = {{convert|1|LT|t|sigfig=7|disp=out}}
| units3 = Short tons
| inunits3 = {{convert|1|LT|ST|sigfig=3|disp=out}} (exactly)
}}
The long ton,{{cite web|url=http://www.msc.navy.mil/inventory/glossary.htm |title=Definitions, Tonnages and Equivalents |work=Military Sealift Fleet Support Command Ships |access-date=11 September 2016 |url-status=dead |archive-url=https://web.archive.org/web/20170724013148/http://www.msc.navy.mil/inventory/glossary.htm |archive-date=24 July 2017 }} also known as the imperial ton, displacement ton,Dictionary.com - "a unit for measuring the displacement of a vessel, equal to a long ton of 2240 pounds (about 1016 kg) or 35 cu. ft. (1 cu. m) of seawater." or British ton,{{Cite web |last=AME |date=2018-04-03 |title=Ton vs Tonne, what's the difference? Which one is heavier? |url=https://www.asseteng.com.au/blog/whats-difference-ton-tonne-one-heavier/ |access-date=2025-04-06 |website=Asset Management Engineers |language=en}} is a measurement unit equal to 2,240 pounds (1,016.0 kg). It is the name for the unit called the "ton" in the avoirdupois system of weights or Imperial system of measurements. It was standardised in the 13th century. It is used in the United States for bulk commodities.
It is not to be confused with the short ton, a unit of weight equal to {{convert|2000|lb|kg|1|lk=on}} used in the United States, and Canada before metrication, also referred to simply as a "ton".
Unit definition
A long ton is defined as exactly 2,240 pounds. The long ton arises from the traditional British measurement system: A long ton is 20 long hundredweight (cwt), each of which is 8 stone {{nowrap|(1 stone {{=}} 14 pounds).}} Thus, a long ton is {{nowrap|20 × 8 × 14 lb {{=}} 2,240 lb.}}
Unit equivalences
A long ton, also called the weight ton (W/T), imperial ton, or displacement ton, is equal to:
- {{convert|2240|lb|kg MT|sigfig=5|abbr=off}}
- exactly 12% more than the 2,000 pounds of the North American short ton, being 20 long hundredweight (112 lb) rather than 20 short hundredweight (100 lb)
- the weight of {{convert|35|ft3|3}} of salt water with a density of {{convert|64|lb/ft3}}
Usage around the world
=United Kingdom=
To comply with the practices of the European Union, the British Imperial ton was explicitly excluded from use for trade by the United Kingdom's Weights and Measures Act of 1985.[http://www.legislation.gov.uk/ukpga/1985/72/contents legislation.gov.uk: Weights and Measures Act 1985] Retrieved 17 January 2013.A Dictionary of Weights, Measures, and Units, edited by Donald Fenna, Oxford University Press The measure used since then is the tonne, equal to 1,000 kilograms.
If still used for measurement, then the word "ton" is taken to refer to an imperial or long ton.{{Cite web|title=Weights and Measures Act 1985|url=https://www.legislation.gov.uk/ukpga/1985/72|access-date=13 September 2021|website=legislation.gov.uk}}
=United States=
In the United States, the long ton is commonly used in measuring the displacement of ships and the shipping of baled commodities and bulk goods like iron ore and elemental sulfur.{{cn|date=April 2024}}
=International=
The long ton was the unit prescribed for warships by the Washington Naval Treaty of 1922; for example, battleships were limited to a displacement of {{convert|35000|LT|t ST|-1}}.
The long ton is traditionally used as the unit of weight in international contracts for many bulk goods and commodities.{{cn|date=April 2024}}