Convert between hundredweights and other major units of mass.

In the United Kingdom and several other Commonwealth countries, 14ᵗʰ – 20ᵗʰ centuries, a unit of mass = 112 pounds, although other values have existed. Abbr, cwt. link to a chart showing relationships between English units of mass used for wool   link to a chart showing relationships between English units of mass

Before approximately the 14ᵗʰ century there were two hundredweights in England, one of 100 pounds, and one of 108 pounds, used for wax, sugar, pepper, cinnamon, nutmegs, and so on (see the Tractatus). In 1340, King Edward III changed the value of the stone from 12½ pounds to 14 pounds (see sack for the reason why). Since a hundredweight is 8 stones, the 100-pound hundredweight became 112 pounds.



They make use of three different sorts of weights at London, for weighing of goods and silver, viz. The great hundred, the hundred, and the weight of Venice.

For what they call the great hundred, they give 112 pound; and in some sorts of goods, only 104 pound, and that only to citizens of London; the strangers, and such Englishmen as are not citizens, having only 100.

But for spiceries, drugs for dyers, and some other such things, strangers and citizens promiscuously have 112 for 100.

When strangers sell their goods, they must deliver them by the king's weights; but when they buy, they must use the merchants weights, which are less than the king's weights. They weigh silver by the weight called the weight of Venice; 12 ounces of which make the mark.

Malachy Postlethwayt.
The Universal Dictionary of Trade and Commerce…, vol 2.
[Incorporates much of Savery's Dictionary.]
London: W. Strahan, J. and B. Rivington, J. Hinton, L. Hawes, etc., 1774.
Unpaginated, under the headword Weight.


In the United States, at least as early as the early 18ᵗʰ century – early 20ᵗʰ century, a unit of mass = 100 pounds avoirdupois, so defined in the laws of many states. Today the term is rarely heard. According to some sources, it was last principally used by fishermen.²

There are two exceptions to the 100-pound value in the U.S.:

1. The federal government used a value of 112 pounds avoirdupois in assessing taxes on imports¹, since that was the unit’s value in the nations from which the imported goods came.

2. The 112-pound hundredweight seems to have also survived for those commodities traditionally measured in 2240-pound long tons (1 long ton = exactly 20 hundredweights), such as anthracite coal. Two states, Ohio and Nevada, specifically exempted pig iron and iron ore in their laws defining the hundredweight, though their laws do not say what the value of the hundredweight for those commodities should be.

The unit of 100 pounds was also sometimes called a short hundredweight, just to avoid confusion, or simply a hundred (the name of the unit in the laws of Maine and Pennsylvania). It is also sometimes called a cental (for example, in the laws of Massachusetts), a name proposed in the United Kingdom in the 19ᵗʰ century for 100 pounds, but probably not in ordinary commerce.

1. Revenue Service, 2951 (1861).

2. Coal Miners’ Pocketbook, 13th ed., page 5.



Their Weights and Measures in all the Aforesaid Colonies and Plantations [“The British Dominions in America and the West Indies”] are the same as those of London, differing only in their Kintals or Hundred Weight; their Hundred being only 100 lb Avoirdupois, and that of London is 112 lb Avoirdupois.

Hayes, 1740, page 214.


Q. Are coarse goods now weighed in buying and selling by gross weight, or 112 lbs. for a cwt. as formerly?

A. They are not: the merchants in all the principal towns and cities in the United States, now buy and sell by neat hundreds, or 100 lbs. for a cwt., and 2000 lbs. for a ton.

Luther Ainsworth.
Practical Mercantile Arithmetic, in which the Theory and Pracrice of Arithmetic are Familiarly Explained and Illustrated by a Great Variety of Mercantile, Mechanical, and Mathematical Problems. Second Ed. revised.
Providence: B. Cranston & Co., 1837.
Page 70.

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