The hundredweight (abbreviation: cwt), formerly also known as the centum weight or quintal, is a British imperial and US customary unit of weight or mass. Its value differs between the US and British 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 (45.36 kg) is used in the United States.
- The long or imperial hundredweight of 8 stone or 112 pounds (50.80 kg) is defined in the imperial system.
The hundredweight has had many values. In England in around 1300, different "hundreds" (centum in Medieval Latin) were defined. The Weights and Measures Act 1835 formally established the present imperial hundredweight of 112 lb.
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 1824 but in 1879 the measure was legalised 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).
In Europe outside British Isles, a centum or quintal was never defined in terms of British units. Instead, it was based on the kilogram or former customary units. It is usually abbreviated q. It was 50 kg in Germany, 48.95 kg in France, 56 kg in Austria, etc. The unit was phased out or metricized after the introduction of the metric system in the 1790s, being occasionally retained in informal use up to mid-20th century.
- "Special Publication 811 (Guide to the SI)". NIST. 3 December 2019. Retrieved 15 February 2020.
- Text of the UK Units of Measurement Regulations 1995 as originally enacted or made within the United Kingdom, from legislation.gov.uk.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.
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