Gallon - wikipedia Gallon Gallon A one - US - gallon gas can showing `` U.S. gallon '' marking ( for US use ), imperial gallons ( for Canadian use ) and litres Unit information Unit of Volume Symbol gal Unit conversions ( imperial ) 1 imp gal in...... is equal to... SI units 4.546090 L US customary units 1.200950 US gal Unit conversions ( US ) 1 US gal in...... is equal to... SI units 3.785412 L Imperial units 0.8326742 imp gal The gallon ( / ˈɡælən / ) is a unit of measurement for liquid capacity in both the US customary units and the British imperial systems of measurement. Three significantly different sizes are in current use : the imperial gallon defined as 7000454609000000000 ♠ 4.54609 litres, which is used in the United Kingdom, Canada, and some Caribbean nations ; the US gallon defined as 231 cubic inches ( 3.785 L ), which is used in the US and some Latin American and Caribbean countries ; and the least - used US dry gallon defined as ⁄ US bushel ( 4.405 L ). While there is no official symbol for the gallon ( as there are for SI units ), gal is in common use. Contents 1 Definitions 1.1 The English system gallons 1.2 The Imperial gallon 1.3 The US liquid gallon 1.4 The US dry gallon 2 Worldwide usage of gallons 3 Relationship to other units 4 History 5 References 6 External links Definitions The gallon currently has one definition in the imperial system, and two definitions ( liquid and dry ) in the US customary system. Historically, there were many definitions and redefinitions. The English system gallons There were more than a few systems of liquid measurements in the pre-1884 United Kingdom. Winchester or Corn Gallon was 272 in3 ( 157 fl oz ) ( 1697 Act 8 & 9 Will III c22 ) Henry VII ( Winchester ) corn gallon from 1497 onwards was 154.80 fl oz Elizabeth I corn gallon from 1601 onwards was 155.70 fl oz William III corn gallon from 1697 onwards was 156.90 fl oz Old English ( Elizabethan ) Ale Gallon was 282 in3 ( 162 fl oz ) ( 1700 Act 11 Will III c15 ) Old English ( Queen Anne ) Wine Gallon was standardized as 231 in3 ( 133 fl oz ) in the 1706 Act 5 Anne c27, but it differed before that : London ' Guildhall ' gallon ( before 1688 ) was 129.19 fl oz Jersey gallon ( from 1562 onwards ) was 139.20 fl oz Guernsey gallon ( 17th century origins till 1917 ) was 150.14 fl oz Irish Gallon was 217 in3 ( 125 fl oz ) ( 1495 Irish Act 10 Hen VII c22 confirmed by 1736 Act Geo II c9 ) The imperial gallon A British petrol pump selling unleaded in Imperial Gallons in the late 20th century The imperial ( UK ) gallon, now defined as exactly 7000454609000000000 ♠ 4.54609 litres ( about 277.42 cubic inches ), is used in some Commonwealth countries and was originally based on the volume of 10 pounds ( approximately 4.54 kg ) of water at 62 ° F ( 17 ° C ). The imperial fluid ounce is defined as ⁄ of an imperial gallon ; there are four quarts in a gallon, two pints in a quart, and 20 Imperial fluid ounces in an imperial pint. The US liquid gallon A fuel station in America displaying fuel prices per US gallons The US gallon is legally defined as 231 cubic inches, which is exactly 7000378541178400000 ♠ 3.785 411 784 liters. A US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 ° F ( 17 ° C ), making it about 16.6 % lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes the US fluid ounce equal to ⁄ of a US gallon. In order to overcome the effects of expansion and contraction with temperature when using a gallon to specify a quantity of material for purposes of trade, it is common to define the temperature at which the material will occupy the specified volume. For example, the volume of petroleum products and alcoholic beverages are both referenced to 60 ° F ( 16 ° C ) in government regulations. The US dry gallon Main article : Dry gallon This dry measure is one - eighth of a US Winchester bushel of 7003215042000000000 ♠ 2150. 42 cubic inches ; it is therefore equal to exactly 268.8025 cubic inches or about 6997440500000000000 ♠ 4.405 L. The US dry gallon is not used in commerce, and is not listed in the relevant statute, which jumps from the dry quart to the peck. Worldwide usage of gallons Typical units of gasoline in each country. Litre US gallon Imperial gallon No data The Imperial gallon was used in everyday life ( and in advertising ) in the United Kingdom until 1994, and less frequently in Canada, including fuel economy expression in advertisements and other official publications. Gallons used in fuel economy expression in Canada and the United Kingdom are Imperial gallons. The gallon was removed from the list of legally defined primary units of measure catalogued in the EU directive 80 / 181 / EEC for trading and official purposes, with effect from 31 December 1994. Under the directive the gallon could still be used -- but only as a supplementary or secondary unit. One of the effects of this directive was that the United Kingdom amended its own legislation to replace the gallon with the litre as a primary unit of measure in trade and in the conduct of public business, effective from 30 September 1995. Ireland also passed legislation in response to the EU directive, with the effective date being 31 December 1993. Though the gallon has ceased to be the legally defined primary unit, it can still be legally used in both the UK and Ireland as a supplementary unit. The Imperial gallon continues to be used as a unit of measure in Anguilla, Antigua and Barbuda, the Bahamas, the British Virgin Islands, the Cayman Is., Dominica, Grenada, Montserrat, Myanmar ( Burma ), St. Kitts & Nevis, St. Lucia, and St. Vincent & the Grenadines. Other than the United States, the US gallon is used in Liberia, Belize, Colombia, The Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Nicaragua, and Peru. The United Arab Emirates started selling gasoline by the litre in 2010, along with Guyana, and Panama in 2013. The two former had used the Imperial gallon and the latter the US gallon until they switched. Antigua and Barbuda plan to switch over to using litres by 2015. Despite its status as a U.S. territory, and unlike American Samoa, the Northern Mariana Islands, Guam, and the U.S. Virgin Islands, Puerto Rico ceased selling gasoline by the US gallon in 1980. In the Turks & Caicos Islands, both the U.S. gallon and Imperial gallon are used, due to an increase in tax duties disguised by levying the same duty on the 3.79 L U.S. gallon as was previously levied on the 4.55 L Imperial gallon. Relationship to other units Both the US liquid and imperial gallon are divided into four quarts ( quarter gallons ), which in turn are divided into two pints. These pints are divided into two cups ( though the imperial cup is rarely used now ), which in turn are divided into two gills ( gills are also rarely used ). Thus a gallon is equal to four quarts, eight pints, sixteen cups or thirty - two gills. The imperial gill is further divided into five fluid ounces, whereas the US gill is divided into four fluid ounces. Thus an imperial fluid ounce is ⁄ of an imperial pint or ⁄ of an imperial gallon, while a US fluid ounce is ⁄ of a US pint or ⁄ of a US gallon. The imperial gallon, quart, pint, cup and gill are approximately 20 % larger than their US counterparts and are therefore not interchangeable. The imperial fluid ounce, on the other hand, is only 4 % smaller than the US fluid ounce and therefore they are often used interchangeably. In the US, liquor is often sold in `` fifths '', which are approximately one - fifth of a US gallon. History The term derives most immediately from galun, galon in Old Northern French, but the usage was common in several languages, for example jale in Old French and gęllet ( bowl ) in Old English. This suggests a common origin in Romance Latin, but the ultimate source of the word is unknown. The gallon originated as the base of systems for measuring wine, and beer in England. The sizes of gallon used in these two systems were different from each other : the first was based on the wine gallon ( equal in size to the US gallon ), and the second on either the ale gallon or the larger imperial gallon. By the end of the 18th century, three definitions of the gallon were in common use : The corn gallon, or Winchester gallon, of about 268.8 cubic inches ( ≈ 4.405 L ), The wine gallon, or Queen Anne 's gallon, which was 231 cubic inches ( ≈ 3.79 L ), and The ale gallon of 282 cubic inches ( ≈ 4.62 L ). The corn or dry gallon was used in the United States until recently for grain and other dry commodities. It is one - eighth of the ( Winchester ) bushel, originally a cylindrical measure of 18 ⁄ inches in diameter and 8 inches in depth. That made the dry gallon ( 9 ⁄ ) × π cubic inches ≈ 6997440488409860128 ♠ 268.802 52 in. The bushel, which like dry quart and pint still sees some use, was later defined to be 2150.42 cubic inches exactly, making its gallon exactly 6997440488377086000 ♠ 268.8025 in ( 6997440488377086000 ♠ 4.404 883 770 86 L ). In previous centuries, there had been a corn gallon of around 271 to 272 cubic inches. The wine, fluid, or liquid gallon has been the standard US gallon since the early 19th century. The wine gallon, which some sources relate to the volume occupied by eight medieval merchant pounds of wine, was at one time defined as the volume of a cylinder 6 inches deep and 7 inches in diameter, i.e. 6 in × ( 3 ⁄ in ) × π ≈ 230.907 06 cubic inches. It had been redefined during the reign of Queen Anne, in 1706, as 231 cubic inches exactly, which is the result of the earlier definition with π approximated to ⁄. Although the wine gallon had been used for centuries for import duty purposes there was no legal standard of it in the Exchequer and a smaller gallon ( 224 cu in ) was actually in use, so this statute became necessary. It remains the US definition today. In 1824, Britain adopted a close approximation to the ale gallon known as the imperial gallon and abolished all other gallons in favour of it. Inspired by the kilogram - litre relationship, the imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury and at a temperature of 62 ° F. In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density 7002998859000000000 ♠ 0.998 859 g / mL weighed in air of density 7000121700000000000 ♠ 0.001 217 g / mL against weights of density 8.136 g / mL ( the original `` brass '' was refined as the density of brass alloys vary depending on metallurgical composition ). This works out at approximately 6997454609030000000 ♠ 4.546 0903 L ( 6997454609028199480 ♠ 277.419 45 in ). The metric definition of exactly 7000454609000000000 ♠ 4.546 09 cubic decimetres ( also 6997454609000000000 ♠ 4.546 09 L after the litre was redefined in 1964, ≈ 6997454609000341471 ♠ 277.419 433 in ) was adopted shortly afterwards in Canada, but from 1976 the conventional value of 6997454609200000000 ♠ 4.546 092 L was used in the United Kingdom until the Canadian convention was adopted in 1985. Historically, gallons of various sizes were used in many parts of Western Europe. In these localities, it has been replaced as the unit of capacity by the litre. Comparison of historic gallons Volume Definition Inverted volume ( gallons per cubic foot ) Approx. weight of water ( pounds per gallon @ 62 ° F ) Cylindrical approximation ( cu in ) ( L or dm ) Diameter ( in ) Height ( in ) Relative error ( % ) 216 ( Roman unciae ) ≈ 7000353960000000000 ♠ 3.5396 Roman congius 8 7.8 5 11 0.01 224 ≈ 3.6707 preserved at the Guildhall, London ( old UK wine gallon ) 7.71 8.09 9 3.5 0.6 231 7000378541178400000 ♠ 3.785 411 784 statute of 5th of Queen Anne ( UK wine gallon, standard US gallon ) 7.48 8.33 7 6 0.04 264.8 ≈ 4.3393 ancient Rumford quart ( 1228 ) 6.53 9.57 7.5 6 0.1 265.5 ≈ 4.3508 Exchequer ( Henry VII, 1497, with rim ) 6.51 9.59 13 0.01 266.25 ≈ 4.3631 ancient Rumford ( 1228 ) 268.8025 7000440488377086000 ♠ 4.404 883 770 86 Winchester, statute 13 + 14 by William III ( corn gallon, old US dry gallon ) 6.43 9.71 18.5 6995100000000000000 ♠ 0.000 01 271 ≈ 4.4409 Exchequer ( 1601, E. ) ( old corn gallon ) 6.38 9.79 4.5 17 0.23 272 ≈ 4.4573 corn gallon ( 1688 ) 277.18 ≈ 4.5422 statute 12 of Anne ( coal gallon ) = ⁄ corn gallons 6.23 10 277.274 7000454345999999999 ♠ 4.543 460 Imperial Gallon ( 1824 ) as originally evaluated. 6.23 10 ≈ 7002277419433000000 ♠ 277.419 433 7000454609000000000 ♠ 4.546 09 standard imperial gallon ( metric ) ( 1964 Canada gallon, 1985 UK gallon ) 6.23 10 52⁄3 11 0.000 2 ≈ 7002277419555000000 ♠ 277.419 555 7000454609200000000 ♠ 4.546 092 Imperial gallon ( 1895 ) Re-determined in 1895, as defined in 1963. 6.23 10 278 ≈ 4.5556 Exchequer ( Henry VII, with copper rim ) 6.21 10.04 278.4 ≈ 4.5622 Exchequer ( 1601 and 1602 pints ) 6.21 10.06 280 ≈ 4.5884 Exchequer ( 1601 quart ) 6.17 10.1 282 ≈ 4.6212 Treasury ( beer and ale gallon ) 6.13 10.2 References Look up gallon in Wiktionary, the free dictionary. Wikimedia Commons has media related to Gallon. Jump up ^ Ricketts, Carl. `` CAPACITY MEASURES OF THE BRITISH ISLES '' ( PDF ). Retrieved 6 September 2016. Jump up ^ `` NIST Handbook 44 - 2012 Edition Appendix C `` General Tables of Units of Measurement '' ``. p. C - 5. Jump up ^ Uniform Laws and Regulations in the areas of legal metrology and engine fuel quality ( PDF ). US Department of Commerce, National Institute of Standards and Technology. 2011. pp. 9 -- 13, 69. Jump up ^ State of New Hampshire Dept of Weights and Measure Archived 13 April 2012 at the Wayback Machine. Jump up ^ 27 CFR section 5.21 Jump up ^ Authorized tables, US Code, Title 15, ch. 6, subchapter I, sec. 205, accessed 19 July 2008. Jump up ^ `` Archived copy ''. Archived from the original on 5 January 2013. Retrieved 6 November 2012. Jump up ^ Statutory Instrument 2001 / 3523 Environmental Protection - The Passenger Car ( Fuel Consumption and CO2 Emissions Information ) Regulations 2001 ( PDF ). The Stationery Office. 30 October 2001. ISBN 0 - 11 - 038743 - 0. Retrieved 1 December 2011. Jump up ^ The Council of the European Communities ( 9 February 2000 ). `` Council Directive 80 / 181 / EEC of 20 December 1979 on the approximation of the laws of the Member States relating to Unit of measurement and on the repeal of Directive 71 / 354 / EEC ''. Retrieved 7 February 2009. The legal units of measurement... for economic, public health, public safety or administrative purposes... litre Jump up ^ `` The Units of Measurement Regulations 1995 ( Article 4 ) ''. 13 July 1995. Retrieved 1 December 2011. Jump up ^ `` Units of Measurement Directive ''. LACORS. 1995. Archived from the original on 24 April 2012. Retrieved 26 November 2011. Jump up ^ `` Guidance Note on the use of Metric Units of Measurement by the Public Sector '' ( PDF ). Department of Trade and Industry. 1995. Archived from the original ( PDF ) on 7 February 2011. Retrieved 20 March 2017. Jump up ^ `` S.I. No. 255 / 1992 -- European Communities ( Units of Measurement ) Regulations, 1992. ''. Irish Statute Book. Office of the Attorney General. 9 September 1992. Retrieved 1 December 2011. Jump up ^ `` Anguilla Renewable Energy Integration Project Final Report '' ( PDF ). Anguilla RE Integration Final Report. Government of Anguilla Ministry of Infrastructure, Communications, Utilities, and Housing ( MICUH ). 19 October 2012. p. 104. Retrieved 13 October 2013. In 2008 -- the most recent year where WTI crude oil averaged US $100 per barrel -- ANGLEC paid an average of about US $4 per imperial gallon ( IG ) for diesel. Jump up ^ `` Budget Statement for 2012 '' ( PDF ). Antigua Observer. 5 December 2011. Archived from the original ( PDF ) on 2 October 2013. Jump up ^ `` The Nassau Guardian ''. Jump up ^ Webmaster. `` Biwater project draws scrutiny ''. Jump up ^ `` Fuel costs driven by factors ''. Jump up ^ `` PHOTO OF THE DAY : Up and up it goes ''. Dominica News Online. Jump up ^ Grenada : Third Review under the Three - Year Arrangement. p. 17. Retrieved 13 October 2013. Jump up ^ `` Gasoline price increases, diesel decreases, cost of living goes up - The Montserrat Reporter ''. Jump up ^ `` Gas prices rise 30 percent in Myanmar for new year ''. Boston.com. Jump up ^ `` GAS PRICES CAPPED UNDER $18 -- LOWEST SINCE JULY ''. The St. Kitts - Nevis Observer. Archived from the original on 24 May 2012. Jump up ^ `` Rotary has a new President - St. Lucia Voice News ''. Archived from the original on 22 December 2015. Jump up ^ `` Another service station sues SOL over fuel volume discrepancy ''. iWitness News. ^ Jump up to : `` International Fuel Prices 2010 / 11 - 7th Edition '' ( PDF ). GTZ Transport Policy Advisory Services on behalf of the ( German ) Federal Ministry for Economic Cooperation and Development. p. 100. Retrieved 16 January 2012. Jump up ^ Badih, Samia ( 30 December 2009 ). `` Petrol stations in UAE go the metric route ''. Gulf News. Retrieved 11 September 2012. Jump up ^ `` Gas prices at Guyoil stations remain below $1,000 mark ''. Caribbean Millers Association. 20 April 2011. Archived from the original on 28 June 2013. Retrieved 20 May 2013. Jump up ^ `` Liters replace gallons at pump as Panama goes metric ''. Newsroom, Panama. 20 April 2013. Archived from the original on 25 May 2013. Retrieved 20 May 2013. Jump up ^ `` The Re-Launch Of Antigua And Barbuda 's Metrication Programme ''. Diversity Global Magazine. 2013. Archived from the original on 16 January 2012. Retrieved 20 May 2013. Jump up ^ `` Gasoline goes up eleven cents per gallon tomorrow ''. Samoa News. Archived from the original on 4 March 2016. Jump up ^ `` Archived copy ''. Archived from the original on 30 October 2006. Retrieved 30 September 2013. Jump up ^ `` UPDATE : Gas prices down 10 cents to $4.73 for a gallon of unleaded ''. Pacific Daily News. Archived from the original on 2013 - 09 - 30. Jump up ^ JOY BLACKBURN ( 16 July 2012 ). `` 7 - cent - per - gallon WAPA tax goes into effect ''. Virgin Islands Daily News. Archived from the original on 30 September 2013. Jump up ^ Pesquera de Busquets, Carmen T ; Barcelo, Carlos Romero ( 14 June 1979 ). `` Order to establish the price of half ( 1 / 2 ) galon ( sic ) of gasoline as transitory measure and that the litter ( sic ) should be the final metric measurement for the sale of gasoline in Puerto Rico '' ( PDF ). San Juan, Puerto Rico : Departamento de Asuntos del Consumidor. Retrieved 21 May 2013. Jump up ^ `` thebahamasweekly.com - New Measures to Improve TCI Finances And Prioritise Spending ''. Jump up ^ E. Frank Henriques, The Signet Encyclopedia of Wine, p. 298 Jump up ^ `` gallon, n. ''. Oxford English Dictionary ( 2 ed. ). Oxford, England : Oxford University Press. 1989. Jump up ^ `` English wine gallon ''. External links Look up gallon in Wiktionary, the free dictionary. 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Question: when did uk change from gallons to litres
Answer: 1994