Work out gold purity value instantly with clear inputs, formula shown and shareable results.
Karat is a fraction of 24, so pure gold content is weight times karat over 24, and the same figure expressed per thousand gives the hallmark fineness. Fineness marks like 916 or 750 are just the karat fraction to three digits, which makes them directly comparable across markets that use different karat conventions.
Pure content
pure grams = weight x karat / 24
Fineness
millesimal fineness = karat / 24 x 1000
pure grams = weight x karat / 24. Karat is a fraction of 24, so pure gold content is weight times karat over 24, and the same figure expressed per thousand gives the hallmark fineness.
Fineness marks like 916 or 750 are just the karat fraction to three digits, which makes them directly comparable across markets that use different karat conventions.
Enter item weight, karat, pure gold price per gram. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.