The ounce (abbreviated oz; apothecary symbol: ) is a unit of mass, weight, or volume used in most British derived customary systems of measurement. The common avoirdupois ounce (approximately 28.3 g) is ​116 of a common avoirdupois pound; this is the United States customary and British imperial ounce. It is primarily used in the United States to measure packaged foods and food portions, postal items, areal density of fabric and paper, boxing gloves, and so on; but sometimes also elsewhere in the Anglosphere.

Besides the common ounce, several other ounces are in current use:

Historically, a variety of different ounces measuring mass or volume were used in different jurisdictions by different trades.


Ounce derives from Latin uncia, a unit that was one-twelfth (​112)[1] of the Roman pound (libra). Ounce was borrowed twice: first into Old English as ynsan or yndsan from an unattested Vulgar Latin form with ts for c before i (palatalization) and second into Middle English through Anglo-Norman and Middle French (unce, once, ounce).[2] The abbreviation oz came later from the cognate Italian word onza (now spelled oncia).

Inch comes from the same Latin word, but differs because it was borrowed into Old English and underwent i-mutation or umlaut ([u] → [y]) and palatalization ([k] → [tʃ]).


Historically, in different parts of the world, at different points in time, and for different applications, the ounce (or its translation) has referred to broadly similar but different standards of mass.

Mass of ounce units
Variant (grams) (grains)
International avoirdupois ounce 28.349523125 437.5
International troy ounce 31.1034768 480
Apothecaries' ounce
Maria Theresa ounce 28.0668  
Spanish ounce (onza) 28.75  
French ounce (once) 30.59  
Portuguese ounce (onça) 28.69  
Roman/Italian ounce (oncia) 27.4  
Dutch metric ounce (ons) 100  
Dutch (pre-metric) ounce (ons) 30  
Chinese metric ounce (盎司) 50  
English Tower Ounce 29.16 450

Currently in use

International avoirdupois ounce

The international avoirdupois ounce is defined as exactly 28.349523125 g under the international yard and pound agreement of 1959, signed by the United States and countries of the Commonwealth of Nations.

In the avoirdupois system, sixteen ounces make up an avoirdupois pound, and the avoirdupois pound is defined as 7000 grains; one avoirdupois ounce is therefore equal to 437.5 grains.

The ounce is still a standard unit in the United States. In the United Kingdom it ceased to be a legal unit of measure in 2000, but is still in general usage on an informal basis. In addition it is the normal measure for portion sizes in British restaurants.[3]

International troy ounce

A troy ounce is equal to 480 grains. Consequently, the international troy ounce is equal to exactly 31.1034768 grams. There are 12 troy ounces in the now obsolete troy pound.

Today, the troy ounce is used only to express the mass of precious metals such as gold, platinum, palladium, rhodium or silver. Bullion coins are the most common products produced and marketed in troy ounces, but precious metal bars also exist in gram and kilogram (kg) sizes. (A kilogram bullion bar contains 32.15074657 troy ounces.)

For historical measurement of gold,

  • a fine ounce is a troy ounce of pure gold content in a gold bar, computed as fineness multiplied by gross weight[4]
  • a standard ounce is a troy ounce of 22 carat gold, 91.66% pure (an 11 to 1 proportion of gold to alloy material)

Metric ounces

Some countries have redefined their ounces in the metric system.[5] For example, the German apothecaries ounce of 30 grams, is very close to the previously widespread Nuremberg ounce, but the divisions and multiples come out in metric.

In 1820, the Dutch redefined their ounce (in Dutch, ons) as 100 grams.[6][7] Dutch amendments to the metric system, such as an ons or 100 grams, has been inherited, adopted, and taught in Indonesia beginning in elementary school. It is also listed as standard usage in Indonesia's national dictionary, the Kamus Besar Bahasa Indonesia, and the government's official elementary‐school curriculum.[8]


Apothecaries' ounce

The obsolete apothecaries' ounce (abbreviated ℥) equivalent to the troy ounce, was formerly used by apothecaries.

Maria Theresa ounce

"Maria Theresa ounce" was once introduced in Ethiopia and some European countries, which was equal to the weight of one Maria Theresa thaler, or 28.0668 g.[9][10] Both the weight and the value are the definition of one birr, still in use in present-day Ethiopia and formerly in Eritrea.

Spanish ounce

The Spanish pound (Spanish libra) was 460 g.[11] The Spanish ounce (Spanish onza) was ​116 of a pound, i.e. 28.75 g.[12]

Tower ounce

The Tower ounce of 450 grains was used in the English mints, the principal one being in the Tower of London. It dates back to the Anglo-Saxon coinage weight standard. It was abolished in favour of the Troy ounce by Henry VIII in 1527.


An ounce-force is ​116 of a pound-force, or 0.2780139 newtons.

The "ounce" in "ounce-force" is equivalent to an avoirdupois ounce; ounce-force is a measurement of force using avoirdupois ounces. However, it is not necessary to identify it as such or to differentiate it in that way because there is no equivalent measure of force using troy or any other "ounce".

Fluid ounce

A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl.) is a unit of volume equal to about 28.4 ml in the imperial system or about 29.6 ml in the US system. The fluid ounce is sometimes referred to simply as an "ounce" in applications where its use is implicit, such as bartending.

Other uses

Fabric weight

Ounces are also used to express the "weight", or more accurately the areal density, of a textile fabric in North America, Asia or the UK, as in "16 oz denim". The number refers to the weight in ounces of a given amount of fabric, either a yard of a given width, or a square yard.[13][14]

Fabric type Typical weight in ounces
Organza, voile, chiffon 1–3
Most cottons, wools, silks, muslin, linen 4–7
Denim, corduroy, twill, velvet 7–16

Copper layer thickness of a printed circuit board

The most common unit of measure for the copper thickness on a printed circuit board (PCB) is ounces (oz). It is the resulting thickness when 1 oz of copper is pressed flat and spread evenly over a one-square-foot area. This roughly equals 34.7 µm.[15]

Notes and references

  1. ^ uncia. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
  2. ^ "ounce". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
  3. ^ "The Units of Measurement Regulations 1995 (Article 4)". 2000-09-20. Retrieved 2009-01-26.
  4. ^ London Bullion Market Association. "Market Basics". Archived from the original on 2012-03-08.
  5. ^ Wittop Koning, D. A.; Houben, G. M. M. (1980). 2000 jaar gewichten in de nederlanden (in Dutch). Lochem-Poperinge: De Tijdstroom. ISBN 9060879651. (in Dutch)
  6. ^ "Guide to The Hague – Where to turn". Archived from the original on 2008-03-16. Retrieved 2008-01-01.
  7. ^ nl:Nederlands metriek stelsel
  8. ^ Ons in KBBI
  9. ^ Greenfield, Richard (1965). Ethiopia: a new political history. F. A. Praeger. p. 327.
  10. ^ Ethiopia observer. 6. 1962. pp. 187–8.
  11. ^ Diccionario de la Real Academia Española, 23rd edition, libra
  12. ^ Diccionario de la Real Academia Española, 23rd edition, onza
  13. ^ "How to shop the fabric market". Retrieved 2008-12-10.
  14. ^ "How Many? A Dictionary of Units of Measurement". Retrieved 2008-12-10.
  15. ^ "Copper Thickness FAQ". Retrieved 2016-11-13.

External links

12 oz. Mouse

12 oz. Mouse is an American surreal humour and psychological thriller animated television series created by Matt Maiellaro for Cartoon Network's late-night programming block, Adult Swim. The series revolves around Mouse Fitzgerald, nicknamed "Fitz" (voiced by Maiellaro), an alcoholic mouse who performs odd jobs so he can buy more beer. Together with his chinchilla companion Skillet, Fitz begins to recover suppressed memories that he once had a wife and a child who have now vanished. This leads him to seek answers about his past and the shadowy forces that seem to be manipulating his world.

In producing the series, Maiellaro crudely designed the characters as a cost-cutting measure; the series is animated by Radical Axis. He intended for the series to lack continuity starting from the pilot, but established a serial format after starting the second episode. He had constructed an ending for the series as well as a detailed map of characters; however, the series finale concluded differently from planned. Maiellaro cast people around his office for the characters, starring himself as the protagonist and Nine Pound Hammer vocalist Scott Luallen as the voice of Roostre; the band also performs the opening theme.

The pilot episode for 12 oz. Mouse, "Hired", premiered on June 19, 2005. The series became a regular staple of Adult Swim's lineup on October 23, 2005, and ended on December 17, 2006. Critical reception was mixed; some praised the series' experimental nature, while others felt confounded by it.

It was announced on September 18, 2018 that the series would return for a half-hour special entitled "Invictus", which aired a month later on October 14. On the day of the special's airing, another announcement was made that the series will return for a 10-episode third season which will air in 2020.

American Arts Commemorative Series medallions

American Arts Commemorative Series Medallions are a series of ten gold bullion medallions that were produced by the United States Mint from 1980 to 1984. They were sold to compete with the South African Krugerrand and other bullion coins.

The series was proposed by North Carolina Senator Jesse Helms after the United States Department of the Treasury began selling portions of the national stockpile of gold. Iowa Representative Jim Leach suggested that the medallions depict notable American artists. President Jimmy Carter signed the bill containing the authorizing legislation into law on November 10, 1978, despite objections from Treasury officials.

The medallions were initially sold through mail order; purchasers were required to obtain the day's price by telephone before ordering. Later, the Mint sold them through telemarketing. Mintage ceased after the ten different medallions approved by Congress were produced. All were struck at the West Point Bullion Depository. The series sold poorly, prompting critics to blame the involved process by which they were first marketed, and the fact that they were medallions rather than coins.

Apothecaries' system

The apothecaries' system or apothecaries' weights and measures is a historical system of mass and volume units that were used by physicians and apothecaries for medical recipes, and also sometimes by scientists. The English version of the system is closely related to the English troy system of weights, the pound and grain being exactly the same in both. It divides a pound into 12 ounces, an ounce into 8 drachms, and a drachm into 3 scruples or 60 grains. This exact form of the system was used in the United Kingdom; in some of its former colonies it survived well into the 20th century. The apothecaries' system of measures is a similar system of volume units based on the fluid ounce. For a long time, medical recipes were written in Latin, often using special symbols to denote weights and measures.

The use of different measure and weight systems depending on the purpose was an almost universal phenomenon in Europe between the decline of the Roman Empire and metrication. This was connected with international commerce, especially with the need to use the standards of the target market and to compensate for a common weighing practice that caused a difference between actual and nominal weight. In the 19th century, most European countries or cities still had at least a "commercial" or "civil" system (such as the English avoirdupois system) for general trading, and a second system (such as the troy system) for precious metals such as gold and silver. The system for precious metals was usually divided in a different way from the commercial system, often using special units such as the carat. More significantly, it was often based on different weight standards.

The apothecaries' system often used the same ounces as the precious metals system, although even then the number of ounces in a pound could be different. The apothecaries' pound was divided into its own special units, which were inherited (via influential treatises of Greek physicians such as Dioscorides and Galen, 1st and 2nd century) from the general-purpose weight system of the Romans. Where the apothecaries' weights and the normal commercial weights were different, it was not always clear which of the two systems was used in trade between merchants and apothecaries, or by which system apothecaries weighed medicine when they actually sold it. In old merchants' handbooks the former system is sometimes referred to as the pharmaceutical system, and distinguished from the apothecaries' system.

Britannia (coin)

Britannia coins are British bullion coins issued by the Royal Mint in gold since 1987 and in silver since 1997.

Britannia gold coins contain one troy ounce of gold and have a face value of £100. Gold Britannias also are issued in fractional sizes of one-half, one-quarter, and one-tenth of a troy ounce and with face values of £50, £25, and £10 respectively. In 2013 two additional sizes were introduced, a five-ounce coin of face value £500, and a fractional size of one-twentieth of face value £5.Britannia silver coins contain one troy ounce of silver and have a face value of £2. Silver Britannias also are issued in fractional sizes of one-half, one-quarter, and one-tenth of a troy ounce and with face values of £1, 50p, and 20p respectively. Like the gold coins in 2013 two additional sizes were introduced, a five-ounce coin of face value £10, and a fractional size of one-twentieth of face value 10p.

Carat (mass)

The carat (ct) (not to be confused with the unit of purity of gold alloys, which is also spelled carat in UK English but usually spelled karat in US English), is a unit of mass equal to 200 mg (0.2 g; 0.007055 oz) and is used for measuring gemstones and pearls.

The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon afterwards in many countries around the world. The carat is divisible into one hundred points of two milligrams each. Other subdivisions, and slightly different mass values, have been used in the past in different locations.

In terms of diamonds, a paragon is a flawless stone of at least 100 carats (20 g).The ANSI X.12 EDI standard abbreviation for the carat is CD.

Fluid ounce

A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl., old forms ℥, fl ℥, f℥, ƒ ℥) is a unit of volume (also called capacity) typically used for measuring liquids. Various definitions have been used throughout history, but only two are still in common use: the British Imperial and the United States customary fluid ounce.

An imperial fluid ounce is ​1⁄20 of an imperial pint, ​1⁄160 of an imperial gallon or approximately 28.41 ml.

A US fluid ounce is ​1⁄16 of a US fluid pint and ​1⁄128 of a US liquid gallon or approximately 29.57 ml, making it about 4% larger than the imperial fluid ounce.

The fluid ounce is distinct from the ounce as a unit of weight or mass, although it is sometimes referred to simply as an "ounce" where context makes the meaning clear, such as ounces in a bottle.

Frank Oz

Frank Oz (born Frank Richard Oznowicz; May 25, 1944) is an American actor, puppeteer, director and producer. His career began as a puppeteer, where he performed the Muppet characters of Miss Piggy, Fozzie Bear, Animal, and Sam Eagle in The Muppet Show, and Cookie Monster, Bert, and Grover in Sesame Street. He is also known for the role of Yoda in the Star Wars series, in which he has performed and provided the voice for the character in several films and television series.

His work as a director includes Little Shop of Horrors (1986), Dirty Rotten Scoundrels (1988), What About Bob? (1991), In & Out (1997), Bowfinger (1999), The Score (2001), Death at a Funeral (2007), and an episode of the US TV series Leverage (2011).

Gold bar

A gold bar, also called gold bullion or a gold ingot, is a quantity of refined metallic gold of any shape that is made by a bar producer meeting standard conditions of manufacture, labeling, and record keeping. Larger gold bars that are produced by pouring the molten metal into molds are called ingots. Smaller bars may be manufactured by minting or stamping from appropriately rolled gold sheets. The standard gold bar held as gold reserves by central banks and traded among bullion dealers is the 400-troy-ounce (12.4 kg or 438.9 ounces) Good Delivery gold bar. The kilobar, which is 1000 grams in mass (32.15 troy ounces), is the bar that is more manageable and is used extensively for trading and investment. The premium on these bars when traded is very low over the spot value of the gold, making it ideal for small transfers between banks and traders. Most kilobars are flat, although some investors, particularly in Europe, prefer the brick shape. Asian markets differ in that they prefer gram gold bars as opposed to Troy ounce measurements. Popular sizes in the Asian region include 10 grams, 100 grams and 1,000 gram bars.

Legality of cannabis by U.S. jurisdiction

In the United States, the use and possession of cannabis is illegal under federal law for any purpose, by way of the Controlled Substances Act of 1970. Under the CSA, cannabis is classified as a Schedule I substance, determined to have a high potential for abuse and no accepted medical use – thereby prohibiting even medical use of the drug. At the state level, however, policies regarding the medical and recreational use of cannabis vary greatly, and in many states conflict significantly with federal law.

The medical use of cannabis is legal (with a doctor's recommendation) in 33 states, four out of five permanently inhabited U.S. territories, and the District of Columbia. Fourteen other states have laws that limit THC content, for the purpose of allowing access to products that are rich in cannabidiol (CBD), a non-psychoactive component of cannabis. Although cannabis remains a Schedule I drug, the Rohrabacher–Farr amendment prohibits federal prosecution of individuals complying with state medical cannabis laws.The recreational use of cannabis is legal in 10 states (Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, and Washington), the District of Columbia, the Northern Mariana Islands, and Guam. Another 14 states plus the U.S. Virgin Islands have decriminalized. Commercial distribution of cannabis is allowed in all jurisdictions where cannabis has been legalized, except Vermont and the District of Columbia. Prior to January 2018, the Cole Memorandum provided some protection against the enforcement of federal law in states that have legalized, but it was rescinded by Attorney General Jeff Sessions.Although the use of cannabis remains federally illegal, some of its derivative compounds have been approved by the Food and Drug Administration for prescription use. Cannabinoid drugs which have received FDA approval are Marinol, Syndros, Cesamet, and Epidiolex. Cannabidiol is also sold by numerous online retailers who claim their products are derived from industrial hemp and therefore legal. Although the Drug Enforcement Administration considers non-Epidiolex CBD a Schedule I drug, it has so far not taken action to shut down these sales.

List of copper alloys

Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. The best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both these are imprecise terms, both having been commonly referred to as lattens in the past. Today the term copper alloy tends to be substituted, especially by museums.

Malt liquor

Malt liquor, in North America, is beer with high alcohol content. Legally, it often includes any alcoholic beverage with 5% or more alcohol by volume made with malted barley. In common usage, it refers to beers containing a high alcohol content, generally above 6%, which are made with ingredients and processes resembling those for American-style lagers.

Mole (unit)

The mole is the base unit of amount of substance in the International System of Units (SI). Effective 20 May 2019, the mole is defined as the amount of a chemical substance that contains exactly 6.02214076×1023 (Avogadro constant) constitutive particles, e.g., atoms, molecules, ions or electrons.This definition was adopted in November 2018, revising its old definition based on the number of atoms in 12 grams of carbon-12 (12C) (the isotope of carbon with relative atomic mass 12 Da by definition). The mole is an SI base unit, with the unit symbol mol.

The mole is widely used in chemistry as a convenient way to express amounts of reactants and products of chemical reactions. For example, the chemical equation 2H2 + O2 → 2H2O can be interpreted to mean that 2 mol dihydrogen (H2) and 1 mol dioxygen (O2) react to form 2 mol water (H2O). The mole may also be used to represent the number of atoms, ions, or other entities in a given sample of a substance. The concentration of a solution is commonly expressed by its molarity, defined as the amount of dissolved substance per unit volume of solution, for which the unit typically used is moles per litre (mol/l), commonly abbreviated M.

The term gram-molecule was formerly used for essentially the same concept. The term gram-atom has been used for a related but distinct concept, namely a quantity of a substance that contains an Avogadro's number of atoms, whether isolated or combined in molecules. Thus, for example, 1 mole of MgBr2 is 1 gram-molecule of MgBr2 but 3 gram-atoms of MgBr2.

More Bounce to the Ounce

"More Bounce to the Ounce" is a song performed by American funk band Zapp. It is the opening track on their eponymous debut album and serves as the album's first single. The song was written, arranged, composed and produced by Roger Troutman; and it peaked at #86 on the Billboard Hot 100 in 1980.The song is featured in the 2002 Rockstar video game Grand Theft Auto: Vice City and the 2018 South Park episode "A Boy and a Priest".

The song title was taken from a 1950s Pepsi ad campaign of the same name.

Per Fine Ounce

Per Fine Ounce is the title of an unpublished novel by Geoffrey Jenkins featuring Ian Fleming's James Bond. It was completed c.1966 and is considered a "lost" novel by fans of James Bond because it was actually commissioned by Glidrose Productions, the official publishers of James Bond. It was rejected for publication, however, missing the opportunity to become the first continuation James Bond novel. The Adventures of James Bond Junior 003½, a novel written by the pseudonymous R. D. Mascott, was later published in 1967 featuring James Bond's nephew; Colonel Sun written by Kingsley Amis under the pseudonym Robert Markham was published in 1968 as the first adult continuation novel following Ian Fleming's The Man with the Golden Gun (1965).

Pittman Act

The Pittman Act was a United States federal law sponsored by Senator Key Pittman of Nevada and enacted on April 23, 1918. The act authorized the conversion of not exceeding 350,000,000 standard silver dollars into bullion and its sale, or use for subsidiary silver coinage, and directed purchase of domestic silver for recoinage of a like number of dollars. Under the Act, 270,232,722 standard silver dollars were converted into bullion (259,121,554 for sale to Great Britain at $1.00 per fine ounce, plus mint charges, and 11,111,168 for subsidiary silver coinage), the equivalent of about 209,000,000 fine ounces of silver. Between 1920 and 1933, under the Act, the same quantity of silver was purchased from the output of American mines, at a fixed price of $1 per ounce, from which 270,232,722 standard silver dollars were recoined. The fixed price of $1 per ounce was above the market rate and acted as a federal subsidy to the silver mining industry.Further provisions relating to silver coinage were contained in the Thomas Amendment to the Agricultural Adjustment Act of 1933.

Pound (force)

The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force or weight used in some systems of measurement including English Engineering units and the British Gravitational System. Pound-force should not be confused with foot-pound, a unit of energy, or pound-foot, a unit of torque, that may be written as "lbf⋅ft"; nor should these be confused with pound-mass (symbol: lb), often simply called pound, which is a unit of mass.

Snow leopard

The snow leopard (Panthera uncia), also known as the ounce, is a large cat native to the mountain ranges of Central and South Asia. It is listed as Vulnerable on the IUCN Red List because the global population is estimated to number less than 10,000 mature individuals and decline about 10% in the next 23 years. It is threatened by poaching and habitat destruction following infrastructural developments.The snow leopard inhabits alpine and subalpine zones at elevations from 3,000 to 4,500 m (9,800 to 14,800 ft), ranging from eastern Afghanistan to Mongolia and western China. In the northern range countries, it also occurs at lower elevations.Taxonomically, the snow leopard was initially classified in the monotypic genus Uncia. Since 2008, it is considered a member of the genus Panthera based on results of genetic studies. Two subspecies were described based on morphological differences, but genetic differences between the two have not been confirmed. It is therefore regarded a monotypic species.

Troy weight

Troy weight is a system of units of mass that originated in 15th-century England, and is primarily used today in the precious metals industry. Its units are the grain, pennyweight (24 grains), troy ounce (20 pennyweights), and troy pound (12 troy ounces). The grain is the same grain used in the more common avoirdupois system. By contrast, the troy ounce is heavier than the avoirdupois ounce, while the troy pound is lighter than the avoirdupois pound.

United States customary units

United States customary units are a system of measurements commonly used in the United States. The United States customary system (USCS or USC) developed from English units which were in use in the British Empire before the U.S. became an independent country. However, the United Kingdom's system of measures was overhauled in 1824 to create the imperial system, changing the definitions of some units. Therefore, while many U.S. units are essentially similar to their Imperial counterparts, there are significant differences between the systems.

The majority of U.S. customary units were redefined in terms of the meter and the kilogram with the Mendenhall Order of 1893 and, in practice, for many years before. These definitions were refined by the international yard and pound agreement of 1959.Americans primarily use customary units in commercial activities, as well as for personal and social use. In science, medicine, many sectors of industry, and some of government and military, metric units are used. The International System of Units (SI), the modern form of the metric system, is preferred for many uses by the U.S. National Institute of Standards and Technology (NIST). For newer units of measure where there is no traditional customary unit, international units are used, sometimes mixed with customary units, such as electrical resistance of wire expressed in ohms (SI) per thousand feet.

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