FREE CALCULATORS › GOLD VALUE & DENSITY TEST
Gold value calculator by karat - with the density test
What is a piece of gold worth? Choose the karat, type in the weight and today's spot price: you get the fine gold, the value and your payout. Below: the density test that spots most fakes.
How it is calculated
fine gold = weight × fineness (18 K = 750 ‰ = 0.750) price per g = spot price per troy ounce / 31.1034768 value = fine gold × price per g; payout = value × payout % density = weight in air / displaced water × density of the water (0.9982 g/cm³ at 20 °C)
Example: 10 g of 18 K gold hold 7.5 g of fine gold. At a spot price of 2,400 per troy ounce (77.16 per g) the piece is worth 578.71, a payout of 90 % is 520.84. A piece of 12.35 g that displaces 0.80 g of water has a density of 15.41 g/cm³ - inside the range of 18 K gold (15.0-16.0).
The fineness values are the usual hallmarks. The density test is a screening, not an assay: plated brass or copper, lead and wrong alloys show up at once, but tungsten has nearly the density of gold - and small pieces have a big uncertainty. Use the finest scale you have.
On the scale it is done while you weigh
In the density mode of UP↑SCALE the scale guides you through every step and takes the values by itself; the app shows the density with the uncertainty of your scale, the closest materials and a fineness estimate. The gold calculator puts the value and the payout next to the weight of every piece, in carat, grain, troy ounce, pennyweight or tola. For jewellers and gold buyers.
More for Jewellers & gold buyers · open the free app · does my scale work?
Gold value and testing: questions and answers
How much fine gold is in 18 karat gold?
75 %: 18 K = 750 ‰. 22 K is 916 ‰, 14 K 585 ‰, 9 K 375 ‰ and 24 K (fine gold) 999 ‰. Multiply the weight of the piece by the fineness to get the fine gold.
How do I calculate the value of scrap gold?
Weight × fineness × the spot price per gram. The spot price is quoted per troy ounce: divide it by 31.1034768 for the price per gram. A buyer pays a share of that value - the payout.
How many grams are in a troy ounce?
31.1034768 g. A troy ounce is heavier than the ounce of the kitchen (28.35 g); precious metals are always priced in troy ounces.
How can I test gold at home with a scale?
With the density test: weigh the piece dry, then the water it displaces (cup of water on the scale, tared, piece hanging on a thread). Density = weight in air / displaced water × 0.998. Pure gold has about 19.3 g/cm³, 18 K about 15.0-16.0.
Can the density test be fooled?
Yes, by tungsten: 19.25 g/cm³ is nearly the density of gold. A gold-plated tungsten bar passes a density test - for bars and big pieces add other tests (ultrasound, conductivity, an assay).
More free calculators
No sign-up, nothing is sent anywhere - the maths runs in your browser. All calculators
Roast loss calculator
The roast loss in %, what a kg of roasted coffee costs you and how much green coffee an order needs.
℮ calculator: TNE, T1, T2
The limits for your nominal quantity, the sample plan for your lot - and the lot check of your weights.
USP <41> minimum weight
Repeatability, minimum weight (2000 s) and accuracy of your balance from your weighings.
Dough temperature (DDT)
The water temperature for your desired dough temperature, with the friction of your mixer.
Cannabis infusion & dose
mg THC and CBD per gram of your butter, oil or tincture - and the infusion for a dose per portion.