Gallon

The gallon is a unit of volume in British imperial units and United States customary units. The imperial gallon (imp gal) is defined as 4.54609 litres, and is or was used in the United Kingdom and its former colonies, including Ireland, Canada, Australia, New Zealand, India, South Africa, Malaysia and some Caribbean countries, while the US gallon (US gal) is defined as 231 cubic inches (3.785411784 L), and is used in the United States and some Latin American and Caribbean countries. There are four gills in a pint, two pints in a quart, and four quarts (quarter gallons) in a gallon, with the imperial gill being divided into five imperial fluid ounces and the US gill being divided into four US fluid ounces: this, and a slight difference in the sizes of the imperial fluid ounce and the US fluid ounce, give different sizes for the imperial gallon and US gallon. The IEEE standard symbol for both the imperial and US gallons is gal, not to be confused with the gal (symbol: Gal), a CGS unit of acceleration.