Imperial hundredweight

The hundredweight (abbreviation: cwt), formerly also known as the centum weight or quintal, is an English, imperial, and US customary unit of weight or mass of various values. Its present value continues to differ 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 "hundredweight".

Under both conventions, there are 20 hundredweight in a ton, producing a "short ton" of 2000 lb and a "long ton" of 2240 lb.

The hundredweight has had many different values. In England in around 1300, various different "hundreds" (centem 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.

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