oz t

troy ounce

Massexact by definition

The troy ounce is exactly 480 grains, which is exactly 31.1034768 grams. It is the trading unit for gold, silver, platinum and palladium worldwide, and a bullion price "per ounce" always means this one.

Watch out: It is about 10 percent heavier than the avoirdupois ounce of 28.349523125 g. That gap is the single most common metals-trade conversion error, and it runs the wrong way from intuition: the troy ounce is heavier, but the troy POUND of twelve troy ounces is lighter than the avoirdupois pound of sixteen.

1 oz t 0.031103477 kg
Where the unit came from

Named for the fairs of Troyes in Champagne, one of the great trading centres of medieval Europe, where the standard was widely accepted and carried home by merchants.