Troy Ounces versus More Common Avoirdupois Ounces

Troy Ounces vs Avoirdupois Ounces

Ever wonder what the difference is between a troy ounce and a regular ‘ol everyday ounce? If so, you’re not the only one as we get asked this question quite often. Simply put, the most commonly used measurement system used for everyday weights, especially in the United States, is called the Avoirdupois weight system. But buyers of gold, silver and other precious metals are used to seeing a different system altogether – Troy weights. Precious metals, and a few other commodities, such as gemstones, are almost always bought and sold throughout the world in troy ounces. It is believed that the troy system of weights originated sometime during the middle ages in Troyes, France.

As for the comparison between the two weights, the measurements are as follows:
   1 avoirdupois ounce = 28.35 grams
   1 troy ounce = 31.10 grams

So as you can see 1 troy ounce actually weighs more than 1 avoirdupois ounce. However, when converting to pounds, the avoirdupois system comes out on top – that’s because there are 16 avoirdupois ounces in 1 avoirdupois pound, whereas there are only 12 troy ounces in 1 troy pound.

Even if this is still a bit confusing, just remember that 1 troy ounce of silver weighs more than 1 ounce of sugar, or grains, or many other commonly weighed everyday items. Now the next time you go to buy bullion, you’ll know what the troy mentioned along with the weight of the coin, round or ingot refers to. But keep in mind, some precious metals don't include the actual term "troy" on the piece because it is an industry standard and the understood method of measuring precious metals - however more often than not it will be mentioned in the description and/or on the certificate of authenticity.