IN PLAIN ENGLISH
How much actual gold, silver, platinum or palladium is in what you hold, once the other metals mixed in are taken out.
FULL DEFINITION
The weight of pure metal in a holding, in troy ounces.
EXAMPLE
A sovereign weighs 7.98805 g and is 22 carat (916.7 parts per thousand gold): 7.98805 × 916.7 ÷ 1000 ÷ 31.1034768 = 0.23543 troy oz of gold. Ten of them hold 2.3543 oz.
HOW IT'S CALCULATED
Fine weight = how many × what one weighs (in grams) × purity ÷ 1000 ÷ 31.1034768, since one troy ounce is exactly 31.1034768 g (a kilogram is 1,000 g). Purity is parts per thousand, as stamped: 999.9 for most gold bars and bullion coins, 916.7 for 22 carat, 750 for 18 carat, 925 for sterling silver. The quick-fill coins use their standard weights: a sovereign 7.98805 g, a half sovereign 3.99403 g and a Krugerrand or American Gold Eagle 33.93 g, all 22 carat, so a Krugerrand holds one troy ounce of gold.
Educational content only. It is not personal financial advice.