How to calculate the gold price per gram

1. From troy ounce to gram

Gold is priced internationally per troy ounce. One troy ounce is 31.1035 grams, so:

gold price per gram = gold price per troy ounce ÷ 31.1035

Right now that is €115.11 per gram of fine gold (live gold price).

2. Take the fineness into account

A piece of 14 carat jewellery contains 58.5% gold. The rest is an alloy of, for example, silver and copper. The metal value per gram is therefore:

value per gram = gold price per gram × fineness

For 14 carat that is currently €67.34 per gram, for 18 carat €86.33 per gram.

3. Example: a 12 gram bracelet

A 14 carat bracelet of 12 grams has a metal value of 12 × €67.34 = €808.04. Stones and clasps made of other materials do not count towards the weight.

4. From metal value to buying or selling price

A gold buyer pays part of the metal value (often 85–96%), because the gold still has to be melted and refined. A jeweller adds a markup for design, labour and margin when selling. In WooCommerce you can set this per product with ZilverGoudPrijs: price × weight × fineness × (1 + markup) + fixed markup.