What is a Troy Ounce?

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When looking to invest in precious metals you may well have
noticed the common use of the term ‘troy ounce’, to weigh
gold bars and as a unit of reference for the gold spot price.

A troy ounce is an imperial unit of measure. It has been the
official weight system for gold and silver since the 16th century,
and is now used for very little else. When the spot price for
gold appears on a chart, then, this will usually refer to the
price per troy ounce (oz t).

Its origins as a unit are not fully known, although it is often
linked to the French city of Troyes, an important trade market
in medieval times and belongs to the troy weights system,
once commonly used across Europe. BullionByPost stocks
a range of one troy ounce gold bars from such LBMA approved
refiners as PAMP, Metalor, and Heraeus among others.

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How much does a troy ounce weigh?

Investors in precious metals should be careful to note the difference between a troy ounce and the common ‘avoirdupois’ ounce, which is still used in some countries such as Great Britain and USA. The troy ounce weighs around 10% (2.75g) more than the standard ounce at 31.1034768g compared to 28.349523125g.

To convert grams into troy ounces, you multiply the number of grams by 0.03215074656863.

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Why do we use them?

A common belief, and one that seems entirely reasonable, is that the troy weight system was created at the famous trade market of Troyes, in France, due to the need for a standard unit of measure for the many traders who came from far and wide. Its specific use in the measurement of precious metals is due to the fact that the value of money used to be fixed by a certain amount of silver. The monetary unit ‘one pound’ contained one troy pound of silver. It seems perfectly logical, then, that this unit of measurement be linked to the value of precious metals. Although the value of money is no longer fixed by precious metals, the troy ounce is still used because of the London Bullion Market Association’s use of beam balances to weigh gold, due to technical difficulties in using metric electronic scales.