
The British imperial gallon (frequently called simply "gallon") is defined as exactly 4.54609 dm 3 (4.54609 litres). Imperial gallon A Shell petrol station selling 2* and 4* (leaded petrol) by the gallon in the UK, circa 1980 Irish gallon was 217 in 3 (125 imp fl oz 3,560 mL) (1495 Irish Act 10 Hen VII c22 confirmed by 1736 Act Geo II c9).Old English (Queen Anne) wine gallon was standardized as 231 in 3 (133 imp fl oz 3,790 mL) in the 1706 Act 5 Anne c27, but it differed before that:.William III corn gallon from 1697 onwards was 156.90 imp fl oz (4,458 mL).Elizabeth I corn gallon from 1601 onwards was 155.70 imp fl oz (4,424 mL).Henry VII (Winchester) corn gallon from 1497 onwards was 154.80 imp fl oz (4,398 mL).There were a number of systems of liquid measurements in the United Kingdom prior to the 19th century. Historically, there were many definitions and redefinitions. The gallon currently has one definition in the imperial system, and two definitions (liquid and dry) in the US customary system. The IEEE standard symbol for both US (liquid) and imperial gallon is gal, not to be confused with the gal (symbol: Gal), a CGS unit of acceleration.

Different sizes of pints account for the different sizes of the imperial and US gallons.

There are two pints in a quart and four quarts in a gallon. the US dry gallon ("usdrygal"), defined as 1⁄ 8 US bushel (exactly 4.404 883 770 86 L).the US gallon (US gal), defined as 3.785 411 784 L, (231 cubic inches) which is used in the United States and some Latin American and Caribbean countries and.the imperial gallon (imp gal), defined as 4.546 09 litres, which is or was used in the United Kingdom, Ireland, Canada, Australia, New Zealand, and some Caribbean countries.

Three different versions are in current use: The gallon is a unit of volume in British imperial units and United States customary units. Gallon" marking (for US use), imperial gallons, and litres (for Canadian use)
