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
Pint varies, but usually contains 425 ml. In Canada, the "pint of beer" served in pubs and bars has long been considered a colloquial term for "a large glass of beer". Legally speaking, after 1873, it was defined as one British imperial pint of 20 imperial ounces. On the other hand, the United States continued to use a smaller 16 imperial ounce pint, while in French Canada after 1873 a "pinte de bière" was defined as a much larger 40 ounce quart of beer, so confusion arose to which was being used. Prior to 1961, bottled beer in Canada was served