Troy Ounce, Definition, History, and Conversion

Anointed Inyang
Anointed Inyang October 28, 2022
Updated 2022/10/28 at 5:53 PM
Troy Ounce

Let’s begin with the definition of a troy ounce. what is it?  A troy ounce is a weighting unit for precious metals that have been used since the Middle Ages. One troy ounce weighs 31.1034768 grams and was first used at Troyes, France, according to the U.K. Royal Mint.

Instead, other goods like sugar and grain are weighed using one standard ounce, also known as the Avordupois ounce, which is somewhat smaller at 28.35 grams.

To ensure that purity requirements and other common measurements endure across time, the troy ounce is still used as the standard unit of measurement in the precious metals market. The troy ounce is frequently denoted by the abbreviations “t oz” or “oz t.”

The etymology of troy ounce

The French market town of Troyes, where English merchants conducted business as least as early as the early ninth century, is likely where the name Troy weight originates. The term “troy” first appears in a 1390 chronicle of the Earl of Derby’s travels through Europe, where it was used to describe the weight of a platter.

An alternative derivation is offered by Charles Moore Watson (1844–1916): The Public Record Commissioners translate “troni ponderacionem” as “troy weight” in The Assize of Weights and Measures (also known as Tractatus de Ponderibus et Mensuris), one of the statutes with an unknown date from the reign of either Henry III or Edward I, therefore before 1307.

Markets are referred to as troni. The English Dialect Dictionary by Wright has the dialect word troi, which means a balance, according to Watson. The term “troy weight” originally related to the tower system; the first mention of the current troy weights is from 1414.

History Of Troy Ounce

The French city of Troyes, a trading center that drew traders from all across Europe and Britain, is said to have given rise to the troy system of weights and measures. In Troyes, 480 grains of barley were used to measure a troy ounce, and 12 troy ounces were equal to one troy pound.

According to some historians, the troy ounce dates back to the Roman era. Romans used bronze bars that could be divided into 12 equal pieces, or “uncia,” each weighing around 31.1 grams, to standardize their monetary system.

From the 10th century on, as Europe’s economic significance increased, traders from throughout the globe began to trade commodities there. Therefore, in order to make commerce considerably simpler, a new standard monetary weight system had to be created.

According to others, the merchants of Troyes used the same weights as their Roman forefathers to model this new monetary system.

King Henry II of England, who was of French ancestry, changed the British coinage system to more closely resemble the French troy system prior to the adoption of the metric system throughout Europe. Troy weights as we know them now were originally used in England in the 15th century, though the system was periodically changed.

The avoirdupois system, which translates to “goods of weight” and was used by the British before the troy system was adopted, was used to weigh both precious metal and non-precious metal objects. The troy ounce was adopted as the accepted unit of measurement for gold and silver in Britain by 1527, and the US did the same in 1828.

Origin of Troy Ounce

Troy Ounce

It is unknown where the troy weight system came from. Although the Champagne fairs at Troyes in northeastern France are presumably where the name originated, the units themselves may have been created further north.

[Needs citation] The Bremen troy weight system and English troy weights were practically identical. (480.8 British Imperial grains made up the Bremen troy ounce.)

Another theory is that the weights were obtained from the Muslim domains via the Gold Dirhem (47.966 British Imperial grains), similar to how King Offa’s weights were obtained from the Silver Dirhem (about 45.0 British grains).

Another theory is that the weights were obtained from the Muslim domains via the Gold Dirhem (47.966 British Imperial grains), similar to how King Offa’s weights were obtained from the Silver Dirhem (about 45.0 British grains).

Watson thinks that the word troy is related to the dialect term troi (balance). Then troy weight is a type of weighing, similar to auncel or bismar weights or other techniques of a like nature. The term “troy weight” then refers to the measurement of small, valuable or powerful items, such as bullion and medications.

Understanding the Troy Ounce

The only troy weighting system unit that is still in use today is the troy ounce. Metal prices, including those for gold, platinum, and silver, are determined by it. As a result, the troy ounce is frequently mentioned when precious metal prices are quoted per ounce.

It was also applied to the measurement of several gemstones. However, the carat system has essentially taken the place of the troy weight method in the field of precious gems and stones.

Measurement units

  • Troy pound (lb t)

Twelve troy ounces make up a troy pound (lb t), which is 5760 grains (373.24172 grams). (An avoirdupois pound weighs 7000 grains, or about 21.53% more, and contains sixteen avoirdupois ounces.)

  • Troy ounce (oz t)

480 grains make up one troy ounce. Since the international yard and pound agreement went into effect on July 1, 1959, the grain measure has been set at exactly 64.79891 milligrams. C-19 [17] So, 480 grains divided by 0.06479891 grams per grain to get 31.10347680 grams in a troy ounce.

A troy ounce is exactly 480 grains multiplied by 437.5 grains to equal 192 grains, or 1.09714 ounces avoirdupois, or 9.7% greater. According to EU Directive 80/181/EEC[18], the Troy ounce for trading precious metals is deemed to be appropriately approximated by 31.10 g.

  • Pennyweight (dwt)

The letter D stands for pennyweight. Twenty pennyweights equal one troy ounce, and one pennyweight weighs 24 grains. There would have been 240 pennyweights to the pound (mass) because the old troy pound had 12 troy ounces, just as there were 240 pennies in the initial pound-sterling.

The tower pound, which is 15/16 of a troy pound, served as the foundation for the English pound sterling prior to 1526. The denarius, an ancient Roman currency that roughly corresponds to a penny, is represented by the letter D in dwt. British pre-decimal pennies, which used the marks £, s, and d to denote pounds, shillings, and pence, can be used to identify the symbol d for penny.

  • Troy grain

There isn’t a particular “troy grain.” A grain, historically made of barley, is the unit of mass used by all Imperial systems. It has a precise weight of 64.79891 milligrams.

  • Mint masses

An Act touching the monies and coins of England, a piece of legislation passed by Parliament on July 17, 1649, legalized mint masses, often known as moneyers’ masses. A grain is equivalent to 20 mites, 24 droits, 20 perits, and 24 blanks.

Troy Ounce and Ounce.

The avoirdupois ounce, also known as the letter “oz,” is a unit of measurement that is frequently used in the US to measure food and other products, with the exception of precious metals. It is equal to 437.5 grains or 28.349 grams. The gram equivalent of a troy ounce, which is somewhat heavier, is 31.1. For little quantities, the difference (2.751) might be negligible, but for large quantities, it might be significant.

A troy ounce, not a standard ounce, is meant when the price of gold is stated as US $653 per ounce. There are 14.6 troy ounces in a pound as opposed to 16 standard ounces since a troy ounce is heavier than a standard ounce. This pound should not be mistaken for a troy pound, which is made up of 12 troy ounces and is lighter.


Weights of diamonds and precious metals are measured in troy ounces. One troy ounce weighs around 10% more than one standard ounce (1.097) The French town of Troyes, a significant trading hub that established the troy ounce as equal to 480 grains of barley in the 16th century, is where the name Troyes originally came from.

Frequently Asked Questions(faqs)

  1. What Is a Troy Pound?

12 troy ounces make a troy pound (while a standard pound is 16 standard ounces). 0.823 troy pounds make up one troy pound.

  1. Which Is Heavier: 1 oz. or 1 Troy Ounce?

About 10% more weight is added to a troy ounce compared to a standard ounce (1.0:1.097).

  1. What Purposes Do Troy Ounces Serve Today?

Even today, precious metals (such gold and silver) and diamonds are measured in troy ounces. The majority of other items either use the metric system or standard ounces.

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