What is Comparison of the Imperial and US customary systems?
The [[Imperial units|imperial]] and [[United States customary units|U.S. customary]] systems are similar, but there are some differences between them. == Volume == The main difference is in units of [[volume]]. The American system has two [[gallon]]s: a wet and a dry one. The imperial gallon is bigger than each of these. However, the imperial [[fluid ounce]] is slightly smaller than the American one. {| |+ Comparison of Imperial and U.S. volume measures !1 U.S. fluid ounce | = 29.573 529 562 5 millilitres || ≈ 1.041 Imperial fluid ounces |- !1 Imperial fluid ounce | = 28.413 062 5 millilitres || ≈ 0.961 U.S. fluid ounce |- !1 liquid U.S. gallon | = 3.785 411 784 litres || ≈ 0.833 Imperial gallon |- !1 Imperial gallon | = 4.546 09 litres || ≈ 1.201 liquid U.S. gallons |- !1 dry U.S. gallon | = 4.404 842 803 2 litres || ≈ 0.968 Imperial gallon |- !1 Imperial gallon | = 4.546 09 litres || ≈ 1.032 dry U.S. gallons |} == Length == The international [[yard]] is exactly 0.9144 [[metre]]s. This definition was agreed upon by the [[United States]], [[Canada]], the [[United Kingdom]], [[South Africa]], [[Australia]] and [[New Zealand]] in 1959. However, the United States continued to use its old length units for [[surveying]] purposes. The US survey [[foot (unit of length)|foot]] is exactly 1200/3937 [[metre]]. == Weight == Another difference is in units of [[mass]]. In Britain people often use the [[stone (unit)|stone]]. One stone is 14 [[Pound (mass)|pounds]]. Eight stones are one hundredweight (112 lb). Twenty hundredweights are one [[ton]]. So one British ton is 2240 pounds. It is very close to the [[tonne]] of the metric system. In the United States people do not use the stone. They usually use a hundredweight of 100 pounds. This hundredweight is also called a ''short hundredweight''. Twenty short hundredweights are one short ton. The British hundredweight is also called the ''long hundredweight'' and the Britsh ton is also called the ''long ton''. ==Related pages== * [[Imperial units]] * [[United States customar