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 ml (20 fluid ounces). With the allowed margin of error of 0.5 fluid ounces, a "pint" that is less than 554 ml of beer is an offence, though—to the detriment of consumers—this regulation is often violated and rarely enforced. After metrication in Canada, companies sold milk and other liquids in metric units so conversion issues could no longer arise. Legally speaking, although some British imperial units are still legally usable in Canada, as a result of Canada's colonial history, the "pint" served in drinking establishments in Canada should be the larger 20 ounce British imperial pint, rather than the smaller