Gold Weight Measurements

Jewelers weigh gold and the metals used for alloying in troy ounces. However, depending on the circumstances, the terms and units of weight referenced may vary. Sadly, I think sometimes this is solely done to keep the average consumer from making quick and accurate calculations.

  • Troy pound = 12 troy ounces
  • 1 troy ounce = 20 pennyweights (dwt)
  • 1 pennyweight (dwt) = 24 grains (gr)
  • 15.43 grains (gr) = 1 gram (gm)
  • 31.10 grams (gm) = 1 troy ounce

Note these equations carefully. In particular, learn the conversions for pennyweight (dwt), grain (gr), and gram (gm). (Don’t confuse the abbreviations of the last two). You’ll find yourself frequently dealing with these three weight references on a “price per ____” basis.

Gold Karat Values

The karat value (K) of a gold item measures the purity of its gold. In other words, it measures the ratio of pure gold to alloy metals. 24K gold is 100% pure. 12K gold has 12 parts gold and 12 parts alloy metal, or 50% purity.

Divide any K value by 24 to determine the purity percentage, or consult the following table.

Karat Parts Gold Percent Gold
24 24/24 100.00%
18 18/24 75.00%
14 14/24