Long Tons (long-ton) to US Hundredweights (cwt-us) 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 US Hundredweight?

The US hundredweight, also called the short hundredweight or cental, is a unit of mass used in North American commerce and agriculture for bulk commodities such as grain, livestock, and cattle feed.

Definition

The US hundredweight is defined as exactly 100 avoirdupois pounds:

$$1\ \text{cwt} = 45.3592\ \text{kg}$$

Precisely, 1 US cwt = 100 lb = 45.359237 kg exactly. Twenty US hundredweights make one US (short) ton of 2000 lb.

Origin and History

The hundredweight has medieval English origins, where a "hundred" of weight varied by commodity and region. North American usage settled on a clean 100-pound unit—hence "short"—diverging from the British long hundredweight of 112 pounds.

Law and Notable Facts

In the United States the hundredweight is legally 100 lb and is standard in commodity pricing; agricultural products such as milk, hogs, and grain are still quoted per hundredweight (cwt). The abbreviation "cwt" uses the Roman numeral C for one hundred.

Real-World Examples and Conversions

Milk is often priced per hundredweight; for example, "$20 per cwt" means per 100 lb (≈45.4 kg). Twenty US hundredweights equal one short ton (907.18 kg). One US cwt is lighter than one UK cwt (≈50.80 kg).