Have you heard a coin’s load being offered in “troy ounces” or “avoirdupois ounces” and wondered, “what’s the difference?!”

Word HistoryAvoirdupois (pronounced avwa-du-pwah) This word comes from the Old French “aveir de peis,” or “goods of weight.” because that most any type of item various other than precious metals, if who lists a weight in ounces, that assumed the this is the measurement castle mean. The most typically held explanation because that the origin of trojan ounces comes not from old Greece, but instead native the city the Troyes, France sometime about the middle ages.

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Turns out, there IS something in a name. Trojan ounces are usually used as soon as weighing precious metals (like in America’s well-known Silver Eagle series). Things favor groceries or every work items are weighed in avoirdupois ounces. Because that example, anytime you action on a range you’re being weighed based upon the avoirdupois system. We’ve used avoirdupois ounces as our every work weight device for for this reason long, it’s no really necessary to point out which kind of ounce we’re measuring in.

It’s like comparing to apologize and… gold.

You can be wonder – however isn’t an oz an ounce? In short, no. An avoirdupois ounce weighs 28.3495 grams, if a troy ounce weighs 31.1035 grams. It’s believed that this is a throwback to the historical importance that precious metals in profession markets, and merchants’ need to have a standard unit of weight for gold, silver, gemstones and also the like.

It could not seem like a good difference in between the two varieties of ounces. However, it does become more noticeable once you start talking about larger amounts. No to mention that that’s once the genuine fun starts – due to the fact that even though a trojan ounce is more than an avoirdupois ounce, a troy pound weighs much less than an avoirdupois pound.

Wait – how’s the possible? the is due to the fact that a troy pound is a specific unit, characterized as 12 trojan ounces. But under the metric system, a pound is 16 ounces.

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So if you measure up pounds in grams:

1 trojan pound = 373.242 grams1 avoirdupois pound = 453.592 grams

It have the right to be a hefty ide to grasp, i know! however it’s crucial information because that anyone who buys precious metal. For this reason the next time you view a gold, silver or copper piece whose load is provided in ounces, be certain you understand if you’re purchase troy, or avoirdupois!


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