The hundredweight (abbreviation: cwt), formerly also known as the centum weight or quintal, is an English, imperial, and American unit of weight or mass of various values. Its value differs between the American and imperial systems. The two values are distinguished in American English as the "short" and "long" hundredweight and in British English as the "cental" and the "imperial hundredweight".
- The short hundredweight or cental of 100 pounds (45.359237 kg) is used in the United States.
- The long or imperial hundredweight of 8 stone or 112 pounds (50.802345 kg) is in informal use in the imperial system, but its use for trade in the UK was ended by Schedule 1, Part VI of the Weights and Measures Act 1985.
The hundredweight has had many values. In England in around 1300, different "hundreds" (centum in Medieval Latin) were defined. The Weights and Measures Act of 1835 formally established the present imperial hundredweight of 112 lb. The use in trade of measures by "cental", "hundredweight", or "quintal" have now been banned in the United Kingdom under the Weights and Measures Act of 1985.
The United States and Canada came to use the term "hundredweight" to refer to a unit of 100 lb. This measure was specifically banned from British use—upon risk of being sued for fraud—by the Weights and Measures Act of 1824 but, in 1879, the measure was legalized under the name "cental" in response to legislative pressure from British merchants importing wheat and tobacco from the United States.
A few decades ago, commodities weighed in terms of long hundredweight included cattle, cattle fodder, fertilizers, coal, some industrial chemicals, other industrial materials, and so on. However, since increasing metrication in most English-speaking countries, it is now less used. Church bell ringers use the unit commonly, although church bell manufacturers are increasingly moving over to the metric system.
Older blacksmiths' anvils are often stamped with a three-digit number indicating their total weight in hundredweight, quarter-hundredweight (28 lb, abbreviated qr), and pounds. Thus, an anvil stamped "1.1.8" will weigh 148 lb (112 lb + 28 lb + 8 lb).
- NIST Guide to the SI.
- Text of the UK Units of Measurement Regulations 1995 as originally enacted or made within the United Kingdom, from legislation.gov.uk. , which reiterates for hundredweight the Text of the Weights and Measures Act 1985 as in force today (including any amendments) within the United Kingdom, from legislation.gov.uk. .
- Chapter VII of the book Men and measures: a history of weights and measures, ancient and modern, by Edward Nicholson (published 1912). Downloadable at Archive.org.
- William J. Murphy. "Tables for Weights and Measurement: Crops". University of Missouri Extension. http://extension.missouri.edu/xplor/agguides/crops/g04020.htm
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- "Scope, Conventions, Abbreviations, etc". Doves Guide for Church Bell Ringers. Retrieved 21 December 2010.
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- "Anvils-6: Marked Weight of Anvils". Getting Started in Blacksmithing. Retrieved 15 December 2014.
- "The Weights and Measures (Guernsey and Alderney) Law, 1991". Retrieved 29 October 2018.