About

In international logistics, the term "hundredweight" (abbreviated as cwt) creates a high risk for error because it refers to two completely different masses depending on the destination. The US Short Hundredweight is defined as 100 pounds (~45.36 kg), while the British Imperial Long Hundredweight is 112 pounds (~50.80 kg). This divergence originated from the British stone system (14 lb) where 8 stones equals one hundredweight.

This tool eliminates ambiguity by calculating both values simultaneously. It is essential for freight forwarders, steel traders, and agricultural exporters dealing with mixed markets (e.g., shipping from the EU to both the US and the UK). Confusing these units can lead to a tonnage discrepancy of over 12%, directly impacting profit margins and load safety calculations.

Formulas

The conversion relies on the precise definition of the pound (lb) in relation to the kilogram.

M_US = m_kg45.359237

M_UK = m_kg50.802345

Where:

M_US is Short Hundredweight (USA/Canada).
M_UK is Long Hundredweight (UK/Imperial).
1 lb = 0.45359237 kg.

Reference Data

Kilograms (kg)	US Short cwt (100 lb)	Imperial Long cwt (112 lb)	Difference (kg)
10 kg	0.220 cwt	0.197 cwt	-
45.36 kg	1.000 cwt	0.893 cwt	~5.44 kg
50.80 kg	1.120 cwt	1.000 cwt	~5.44 kg
100 kg	2.205 cwt	1.968 cwt	~12% variance
500 kg	11.023 cwt	9.842 cwt	-
1,000 kg	22.046 cwt	19.684 cwt	-
5,000 kg	110.231 cwt	98.421 cwt	-

Frequently Asked Questions

If you are trading with the USA or Canada, use the "US Short cwt" (100 lbs). If you are dealing with the UK or older Commonwealth documentation, use the "Imperial Long cwt" (112 lbs). Always verify the contract definition.

It is most common in livestock (cattle pricing), steel plates, and certain grains. It is less common in finished retail goods, which usually use pure kg or lbs.

The British system uses the "Stone" (14 lbs) as a base. One Hundredweight was defined as 8 Stones ($8 \times 14 = 112$). The US simplified this to a flat 100 lbs for easier decimal calculations.