Comparison of the imperial and US customary measurement systems adopted a system based on the 231-cubic-inch wine gallon for all fluid purposes. This became the US fluid gallon. Both the imperial and US fluid gallon are divided into 4 quarts, 8 pints or 32 gills. However, whereas the US gill is divided into 4 US fluid ounces, the imperial gill is divided into 5 imperial fluid ounces. So whilst the imperial gallon, quart, pint and gill are about 20% larger than their US fluid measure counterparts, the fluid ounce is about 4% smaller. Note that one avoirdupois ounce of water has an approximate volume of one imperial fluid ounce
Cooking weights and measures Note that measurements in this section are in imperial units. Traditional British measures distinguish between weight and volume. American cooks using British recipes, and vice versa, need to be careful with pints and fluid ounces. A US pint is 473 mL, while a UK pint is 568 mL, about 20% larger. A US fluid ounce is of a US pint (29.6 mL); a UK fluid ounce is UK pint (28.4 mL). This makes an Imperial pint equivalent to 19.2 US fluid ounces. On a larger scale, perhaps for institutional cookery, an Imperial gallon is eight Imperial pints (160 imp fl