Convert volume instantly, with the working shown.
Metric volume is clean: a litre is 1,000 millilitres and also exactly 1,000 cubic centimetres, so litres and cubic measures interchange without friction. Imperial volume is where the difficulty lies, because the United States and the United Kingdom use different gallons. A US liquid gallon is about 3.785 litres; an imperial gallon is about 4.546 litres, roughly twenty per cent larger. The same applies down the scale to pints and fluid ounces.
This is a genuine source of error rather than a curiosity. A recipe calling for a pint of milk means 473 millilitres in American usage and 568 in British. Fuel economy figures quoted in miles per gallon are not comparable between the two systems without conversion, and US figures look worse than they are when read as imperial. Complicating it further, a US fluid ounce is about 29.57 millilitres while an imperial fluid ounce is about 28.41 — so the imperial gallon is larger even though its fluid ounce is smaller, because an imperial gallon contains 160 of them against the US gallon's 128.
They derive from different historical standards. A US liquid gallon is about 3.785 litres and an imperial gallon about 4.546, so the imperial gallon is roughly twenty per cent larger. The difference carries down to pints and fluid ounces.
About 473 in US usage and about 568 in imperial. Recipes and drink measures differ accordingly, which is a common source of confusion between American and British sources.
Yes, exactly. A litre is defined as one cubic decimetre, which is 1,000 cubic centimetres, so metric volume and cubic measures convert without any awkward factor.
Because miles per gallon uses a different gallon in each system. A US mpg figure converts to a higher imperial mpg number for identical real consumption, so the two must be converted before comparison.