A coin can weigh more than the gold it contains. Here is how to find the pure gold content, and why it is the number that decides the melt value.
Short answer: the pure gold in a coin is its total weight multiplied by its fineness. Many one-ounce gold coins are made to contain exactly one troy ounce of pure gold, which can mean the whole coin weighs a little more than 31.1 grams if it is alloyed.
Total weight is what the coin weighs on a scale. Fine weight, called the actual gold weight, is the pure gold inside. Coins in alloys such as 22 karat weigh more in total than their fine weight, because the alloy adds other metal for hardness.
Fine weight equals total weight times fineness. A coin that weighs 33.9 g at 0.9167 fineness holds about 31.1 g of pure gold, which is one troy ounce. Check the mint's published specification for each coin to be sure.
Melt value depends only on the fine weight. Use the gold melt value calculator with the fine weight, or with the total weight and the fineness. See also the glossary entry on alloy.
The coin's face usually states the metal, the weight of fine gold and the fineness. Compare it with the mint's specification, and weigh the coin to be sure it matches.
When comparing coins and bars, divide the price by the fine gold in grams, not the total weight. Our guide on comparing coins and bars by cost per gram explains it step by step.
Cost basis, live spot prices and photo documentation. Free for up to 20 holdings.
Open your vault — free