Gold calculator
Fineness is simply parts per thousand. 585 means 585 grams of gold in every kilogram of alloy. The arithmetic is easy; knowing what the answer is worth is the hard part, and that is at the bottom of the page.
Weighing a piece that has stones in it
A gross weight includes everything: metal, stones, enamel, and the dirt of a century. For a rough deduction, a round diamond of one carat weighs 0.2 grams and measures about 6.5 mm across, and most small accent stones in antique jewelry weigh a few hundredths of a gram each. Coloured stones are denser than diamond; a sapphire of the same size weighs roughly a fifth more.
If the piece is largely stone - a big garnet cluster, a carved coral - the metal figure will be badly wrong, and no calculator can fix that from a single number.
Why the melt figure is the floor and not the price
Three deductions sit between the number above and cash in your hand. A refiner buys below spot, typically at 70 to 90 per cent, because refining is a business. A high street gold buyer sits below that again. And VAT or local tax may apply to the transaction depending on where you are.
Against that, the same piece intact may be worth several times its metal. Workmanship, era, maker, the stones and simple desirability all sit on top of the metal and none of them survive the crucible. The calculation that matters is not what the gold weighs but whether the object is worth more than its gold - and for anything made before about 1940 the answer is usually yes. That question is worked through in what is my jewelry worth.
Frequently asked questions
What does 585 mean on gold?
585 means the alloy is 58.5 per cent pure gold by weight, which is the same standard as 14 carat. A 12 gram ring marked 585 contains 7.02 grams of pure gold.
How do I convert carat to fineness?
Divide the carat figure by 24 and multiply by 1000. 18 carat is 18 divided by 24, which is 0.75, so 750 parts per thousand. 9 carat is 375, 14 carat is 585, and 22 carat is 916.
Is melt value the same as what a jeweler will pay me?
No. Melt value is the theoretical worth of the raw metal at the current spot price. A buyer pays a margin below that, commonly 70 to 90 per cent of spot for scrap, because they carry the cost and risk of refining.
Should I sell antique jewelry for its gold weight?
Usually not. Anything made before roughly 1940, and any piece with good workmanship, a known maker or original stones, is normally worth more sold as an object than as metal. Melting is irreversible, so it is the one decision that cannot be revisited.