Gallon

Row with milk packed in 1-gallon American drums. The label also shows the equivalence in liters.

The gallon (symbol gal) is a unit of volume used in English-speaking countries (especially the United States) or influenced by them (such as Liberia, Guatemala, Panama, Puerto Rico, the Dominican Republic, Honduras, Nicaragua, Peru, El Salvador and Colombia), to measure volumes of liquids, mainly gasoline and its price. In the old days, the volume of a gallon depended on what was measured, and where. However, by the 19th century there were two definitions in common use: "gallon of wine" (wine gallon) and "British beer gallon" (ale gallon).

The IEEE standard symbol for both the US liquid gallon and the imperial gallon is gal, which should not be confused with the unit gal (symbol: Gal), which is the unit of acceleration in the CGS system.

Etymology

The word gallon comes from the English gallon and this from the French gallon which means liquid measure, in turn from the late Latin galus (measure of wine) and from Vulgar Latin galla (vessel). In Proto-Indo-European kel (chalice) comes from the Greek κύλιξ (kúlix, chalice) Sanskrit कलश (kalaśa, jug).

Definitions

The gallon currently has one definition in the imperial system and two definitions (liquid and dry) in the US common system. Historically, there have been many definitions and redefinitions.

Imperial or British gallon

Gas measure by:LiterU.S. Gal. U.S.Imperial gallonNo information

In 1824, Great Britain adopted an approximation of the gallon of beer known as the imperial gallon. This gallon was based on the volume of 10 pounds (4.53 L) of distilled water weighed in air, with a barometric pressure of 30 inches of mercury (1016 millibars/mbar or 101.6 kPa) and a temperature of 62° F (16.667 °C), resulting in 277.41945 cubic inches (1 inch = (2.54 cm), one cubic inch = 16.387064 cm³).

An imperial or British gallon also in the Anglo-Saxon system is equivalent to:

• 4,5460902819948 litres (rounded to 4,5461 litres).
• 0.028571428571429 British barrels
• 4 British quarters
• 8 British paints
• 32 British gills
• 160 British liquid ounces

US gallon

Liquid gallon

The US liquid gallon USgal (often called simply "gallon") is legally defined as 231 cubic inches, which is exactly 3.785411784 liters. A gallon of water weighs approximately 8.34 pounds (3.78 kg) at 62 °F (16.66 °C), making it approximately 16.6% lighter than the imperial gallon.

There are 4 quarts in a gallon, 2 pints in a quart, and 16 ounces in 1 pint, making 1 ounce equal to 1/128 US gallon.

To overcome the effects of expansion and contraction with temperature when using a gallon to specify a quantity of material for commercial purposes, 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 referenced to 60°F (15.6°C) in government regulations.

In addition to the United States, the countries of Puerto Rico, Panama, Peru, Colombia, Ecuador and Venezuela use the definition of a gallon which is equivalent to:

• 3,785411784 litres (rounded to 3,7854 litres)
• 0.0238095238095240 American barrels
• 8 American paints
• 32 American gills

Dry gallon

The dry gallon, also known as the corn gallon or grain gallon, is a historical British measure of dry volume used to measure grain and other dry goods and whose official definition was earliest recorded in 1303., was the volume of 8 pounds (4.53 kg) of wheat. It is not used in the US traditional system, although it does exist implicitly, but without authoritative recognition in metering law. The US liquid gallon is about 14.1% smaller than the dry gallon, while its imperial counterpart is about 3.2% larger.

Its default value in the US system was originally 1/8 Winchester bushel, which was a cylindrical measurement 18.5 inches (0.45 m) in diameter and 8 inches (0.2 m) deep, which which made the dry gallon an unknown number of cubic inches. Since the bushel was later defined to be exactly 2150.42 cubic inches, this figure became the exact value of the dry gallon (4.40488377086 L).

Differences between imperial and American

Both gallons equal 8 pints, although in the United States a pint equals 16 fluid ounces, while an imperial pint equals 20 fluid ounces. Thus, the US gallon equals 128 fluid ounces, while the imperial gallon equals 160. This means that the US fluid ounce is 1.8047 cubic inches, and the imperial is 1.7339 cubic inches. Thus, the US fluid ounce is larger than the Imperial, although the US gallon is smaller. However, both are currently used as universal measures, with the American being the best known.

British gallon of beer

Used to measure the volume contained in a beer container. It is still used in the UK and equals 282 cubic inches, or 4.621152048 litres.

History

A plastic container for American milk with a volume of an American gallon.

The term derives more immediately from galun, galon in Old Norman French, but the usage was common in several languages, for example jale in Old French and gęllet (bowl) in Old English. (bowl) in Old English. This suggests a common Romance Latin origin, but the ultimate source of the word is unknown.

The gallon originated as the basis for wine and beer measurement systems in England. The gallon sizes used in these two systems were different from each other: the first was based on the gallon of wine (equal in size to the US gallon), and the second on the larger gallon of beer or imperial gallon.

At the end of the 18th century, there were three definitions of gallon in common use:

• The "maize cantaloupe" or "Winchester cantaloupe" of approximately 268.8 inches cubic. (≈ 4.405 L),
• The Wine galonor Queen Anna's galon, it was 231 cubic inches (≈ 3.785 L), and
• The gallon of beer with 282 cubic inches (≈ 4.622 L).

The "gallon of corn" or "dry gallon" it is used (along with the dry quart and pint) in the United States for grain and other dry goods. It is one-eighth of a bushel (Winchester), originally defined as a cylindrical measure of 18 1< /span>/2 inches in diameter and 8 inches deep, making the dry gallon 8&nbsp;in × (< span lang="en" style="white-space:nowrap; font-family:FreeSerif,'Linux Libertine','Times New Roman',serif; font-size:118% ">9 1/4 in)² × π ≈ 2150.42017 cubic inches. Later, the bushel was defined as exactly 2,150.42 cubic inches, making its gallon exactly 268.8025 in³ (4.40488377086 L); in earlier centuries there was a gallon of corn between 271 and 272 cubic inches.

The wine gallon, fluid gallon, or liquid gallon has been the standard U.S. gallon since the early 19th century. The gallon of wine, which some sources relate to the volume occupied by eight medieval merchant pounds of wine, was once defined as the volume of a cylinder 6 inches deep and 7 inches in diameter, or 6 in × (3 1/2 in)² × π ≈ 230,907 06 cubic inches. It was redefined during the reign of Queen Anne in 1706 as exactly 231 cubic inches, the earlier definition with π approximated to 22/7.

${displaystyle pi r^{2}happrox {frac {22}{7}{7}times left({frac {7}{2}}}{2}}{2}times 6=231}$

Although the gallon of wine had been used for centuries for import duty purposes, there was no legal standard for it in the Exchequer, whereas a smaller 224 in³, which required this statute; the 231 cubic inch gallon is still the American definition today.

In 1824, Great Britain adopted an approximation to the allegan gallon known as the imperial gallon, abolishing all other gallons in favor of it. Inspired by the kilogram-liter relationship, the imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer at 30 inches of mercury and a temperature of 62 degrees Fahrenheit (16.7 °C).).

In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density 0.998859 g/mL weighed in air of density 0.001217 g/mL against weights of density 8.136 g/mL. (the original 'brass' was refined as densities of brass alloys vary based on metallurgical composition), which was calculated as 4.546091879 L to ten significant figures.

The precise definition of exactly 4.54609 cubic decimeters (also 4.54609 L, ≈ 277.419433 in³) came after the liter was redefined in 1964. It was adopted soon after in Canada and in 1976 in the UK.

Use in the world

Gas units used in the world:litreGalón USAImperial gallonwithout data

Imperial gallon

As of 2021, the imperial gallon is still used as the standard unit of gasoline in four British Overseas Territories (Anguilla, the British Virgin Islands, the Cayman Islands, and Montserrat) and six countries (Antigua and Barbuda, Dominica, Grenada, Saint Kitts and Nevis, Saint Lucia, and Saint Vincent and the Grenadines).

All countries and territories that use the imperial gallon as their unit of measurement for gasoline also use miles per hour for speed limits and drive on the left side of the road.

The United Arab Emirates stopped selling gasoline in imperial gallons in 2010 and switched to the liter, and Guyana followed suit in 2013.

Burma subsequently switched from the imperial gallon to the liter in 2014.

Antigua and Barbuda has proposed to switch to trading gasoline by the liter since 2015.

The gallon was removed from the list of legally defined primary units of measurement listed in EU Directive 80/181/EEC for commercial and official purposes, effective December 31, 1994. One of The effects of this directive was that the United Kingdom amended its own legislation to replace the gallon with the liter as the primary unit of measurement in trade and in the conduct of public affairs, with effect from 30 September 1995. However, in the United Kingdom and Ireland, barrels and large containers of beer, oil, and other liquids are often in multiples of an imperial gallon.

Ireland also passed its legislation in response to the EU directive, with an effective date of 31 December 1993. Although the gallon is no longer a primary unit of trade, it can still be used legally in both the United Kingdom as in Ireland as a supplementary unit.

Miles per imperial gallon is used as the primary unit of fuel economy in the UK and as a supplementary unit in Canada in official documentation.

In the Middle East, bottles of chilled water are sold in multiples of the imperial gallon.

US Liquid Gallon

In addition to the United States, gasoline is sold by the gallon in Belize, Colombia, the Dominican Republic, Ecuador, Guatemala, Haiti, Honduras, Nicaragua, and Peru, as well as the Marshall Islands, the Federated States of Micronesia, and Palau, associated with the United States. In Liberia, a former protectorate of the United States, this is also the case.

Puerto Rico stopped selling gasoline in US gallons in 1980.

Despite its status as a U.S. territory, and unlike American Samoa, the Northern Mariana Islands, Guam, and the U.S. Virgin Islands, they also stopped selling gasoline in U.S. gallons.

Panama stopped selling gasoline in US gallons in 2013 and now uses liters, while El Salvador followed suit in June 2021

Both the US gallon and the Imperial gallon are used in the Turks and Caicos Islands due to a tax increase that was disguised by taxing the US gallon (3.79 L) with the same tax that was previously applied to the Imperial gallon (4.55l).

The Bahamas also uses both the US and Imperial gallons.