Long Tons (long-ton) to UK Hundredweights (cwt-uk) conversion

What is the Long Ton?

The long ton is a unit of mass in the British imperial system, historically used for weighing bulk commodities such as coal, ore, and shipping cargo. It is equal to 2,240 pounds and remains familiar in the United Kingdom and in maritime contexts.

Definition

The long ton is defined as exactly 2,240 pounds avoirdupois. Since one pound equals 0.45359237 kg exactly, its SI value is:

$$1\ \text{long-ton} = 1016.05\ \text{kg}$$

Equivalently, the long ton equals 20 hundredweight (cwt) of 112 lb each, distinguishing it from the 2,000 lb US short ton and the 1,000 kg metric tonne.

Origin and History

The long ton descends from the medieval English "tun," a large cask used to ship wine, whose full weight was standardized in trade. The avoirdupois system fixed the hundredweight at 112 pounds (eight stone of 14 lb), and twenty of these made the ton, giving 2,240 lb. This "long" hundredweight and ton became the standard for British commerce and were carried throughout the Commonwealth and colonial trade.

Law and Notable Facts

The long ton is the British/imperial ton, contrasted with the 2,000 lb US short ton and the 1,000 kg metric tonne (megagram). It is legally recognized in the United Kingdom, though the metric tonne has largely replaced it for official trade. Notably, the long ton (1016 kg) sits remarkably close to the metric tonne (1000 kg), differing by only about 1.6%, which is why "ton" and "tonne" are often used loosely as near-equivalents in shipping.

Real-World Examples and Conversions

• A long ton equals 1016.05 kg, about 16 kg heavier than a metric tonne.
• Ship displacement and cargo were traditionally quoted in long tons; a 10,000 long ton vessel carries roughly 10,160 metric tonnes.
• One long ton (2,240 lb) is 240 lb heavier than one US short ton (2,000 lb), a 12% difference.
• A long ton of coal (1016 kg) is a typical unit still cited in older British mining and heating records.

What is the UK Hundredweight?

The UK hundredweight, also called the long hundredweight, is a British imperial unit of mass historically used for coal, agricultural produce, and other bulk goods.

Definition

The UK hundredweight is defined as exactly 112 avoirdupois pounds:

$$1\ \text{cwt} = 50.8023\ \text{kg}$$

Precisely, 1 UK cwt = 112 lb = 8 stone = 50.80234544 kg exactly. Twenty long hundredweights make one long (imperial) ton of 2240 lb.

Origin and History

The value of 112 pounds arose so that the hundredweight would divide evenly into quarters of 28 lb and into stones of 14 lb, easing trade calculations. This "long" hundredweight became standard in Britain and the Commonwealth, in contrast to the North American 100-pound "short" hundredweight.

Law and Notable Facts

Under the British imperial system the hundredweight is legally 112 lb. Its neat divisibility into 4 quarters, 8 stone, or 16 pieces of 7 lb made it convenient before decimalization; it remains recognized for certain traditional trades.

Real-World Examples and Conversions

A traditional bag of coal was often one hundredweight (112 lb, ≈50.8 kg). Twenty UK hundredweights equal one long ton (1016.05 kg). The UK cwt is about 12% heavier than the US cwt of 100 lb (≈45.36 kg).