Troy ounce and ounce, what exactly is the difference?

Investors who are new to the precious metals market often make the mistake of thinking that a troy ounce equals an ounce, however, this is not the case. Many people are confused when they find out that the product they have bought weighs more than a normal ounce. However, this is not surprising as most products sold in troy ounces refer to ounces. The troy ounce is such an ‘industry standard’ that precious metal sellers always refer to a troy ounce, even when they speak of an ounce. At The Silver Mountain, we sell gold and silver 1 troy ounce investment coins.
 

History of the troy ounce

A definitive answer to the question of where the troy ounce comes from has never been clarified with certainty. Some believe that the troy ounce has its origins in the Roman monetary system. During the Roman Republic, one of the first coinage systems in Roman times, the ‘Aes Grave’, was developed. These so-called coins consisted of heavy bronze ingots, one twelfth of which was called a ‘uncia’, or ounce.
 
However, the most accepted assumption is that the term troy ounce originated in the medieval French city of Troyes. Troyes was a trading city in north-eastern France that was important for trading precious metals. Traders needed a standard measure that would distinguish precious metals from other products. Soon the system spread to other countries, creating different versions of troy weights. These included the Holland Troy system, the Paris Troy system and, most significantly, the British Troy system.
 
In Britain, the system was officially adopted as the unit of measurement for gold and silver and the British coinage system in 1527. In the 19th century, when the ‘Imperial Standard System’ was introduced, the troy ounce was also incorporated. From then on, it is unclear how the Troy weight system became the standard for the global precious metals market. The most logical explanation is that Britain colonised much of the world and thus also transferred its culture to these countries.
 

The difference between the troy ounce and the ounce

A troy ounce weighs about 10% more than an ounce, a significant difference is when it comes to precious metals. The troy weight system includes the troy grain, the pennyweight (24 troy grains), the troy ounce (20 pennyweights) and the troy pound (12 troy ounces). This can cause confusion, as the normal pound corresponds to 16 ounces. This makes a troy pound lighter than a pound, while a troy ounce is heavier than an ounce. To avoid all this confusion, troy ounces or kilograms are mainly referred to in the precious metals trade and the term pound is mostly avoided.
 
1 ounce (oz) = 28.349 grams
1 troy ounce (troy oz) = 31.103 grams
1 troy oz = 1.097 oz

Disclaimer: The Silver Mountain does not provide investment advice and this article should not be considered as such. Past performance is no guarantee of future results.