Editing Gallon (section)

===Imperial gallon===
[[File:Shell petrol station in the UK.jpg|thumb|A Shell petrol station selling 2* and 4* (leaded petrol) by the gallon in the UK, circa 1980]]
The British imperial gallon (frequently called simply "gallon") is defined as exactly 4.54609 litres.<ref name=W&M1985>{{cite web|title=Weights and Measures Act 1985, chapter 72, schedule 1|url=https://www.legislation.gov.uk/ukpga/1985/72/schedule/1|website=legislation.gov.uk|publisher=The National Archives on behalf of HM Government|access-date=7 June 2019}}</ref> It is used in Britain and some other [[Commonwealth of Nations|Commonwealth countries]], and until 1976 was defined as the volume of water at {{cvt|62|F|1|abbr=out}}<ref name=BS350Foreword>{{cite book|title=BS 350:Part 1:1974 Conversion factors and tables Part 1. Basis of tables. Conversion factors|date=1983|publisher=British Standards Institution|page=Foreword|edition=AMD 4153|quote=Before that date (November 1976) the definition in the Weights and Measures Act 1963 was such that the gallon could be calculated to be 4.546 091 879 dm<sup>3</sup> to ten significant figures... The return, in November 1976, by precise definition to what had earlier been used as an approximation for the value of the gallon (i.e. 4.546 09 dm3)...}}</ref><ref>{{cite book|title=BS 350:Part 1:1974 Conversion factors and tables Part 1. Basis of tables. Conversion factors|date=1974|publisher=British Standards Institution|page=10|edition=prior to Amendment No.1 1983|quote=the UK gallon (imp gal), defined in Schedule 1 of the Weights and Measures Act 1963, as the space occupied by 10 pounds of distilled water under certain conditions specified in the schedule.}}</ref> whose mass is {{convert|10|lb|sigfig=8}}. 

There are four [[imperial quart]]s in a gallon, two [[imperial pint]]s in a quart, and 20 imperial [[fluid ounce]]s in an imperial pint,<ref name=W&M1985/> making an imperial fluid ounce {{sfrac|160}} of an imperial gallon.