How many ounces in a troy ounce?
Even after someone tells you there are 12 ounces in a Troy pound, you will be left scratching your head in wonder. You asked how many ounces were in a Troy ounce. Well an ounce is not quite always an ounce. The Troy system of weight came about in Troyes, France. It is a system based on units of mass and is used for precious metals as well as gems and of all other possible things, gun powder! When you measure anything else, you are using the avoirdupois system of weighing. A grain is always a grain regardless of weight system, so to make this understandable I’ll use grains. In avoirdupois (AV from now on) an ounce weighs 437.5 grains. In Troy an ounce weighs 480 grains. So in reality, there is a difference in the weight of an ounce. An AV ounce is about 10% lighter than a Troy ounce. In grams, it goes like this: AV=28.35 grams Troy=31.10 grams So there is your difference, and the answer to your question is, there is .9 ounces AV in one ounce Troy.
