Gold Purity

Gold jewellery is made in different purities. You will need to know what carat your gold is. We will use 10ct 14ct and 18ct as our examples on how to calculate the value. 24k is pure gold. Note: 9/24 means 9 divided by 24.

9ct (9/24) = 0.375 therefore 9ct gold is 37.5% pure gold.

10ct (10/24) = 0.41666 therefore 10ct gold is 41.7% pure gold.

14ct (14/24) = 0.58333 therefore 14ct gold is 58.3% pure gold.

15ct (15/24) = 0.625 therefore 15ct gold is 62.5% pure gold.

18ct (18/24) = 0.750 therefore 18ct gold is 75% pure gold.

22ct (22/24) = 0.91667 therefore 22ct gold is approximately 91.7% pure gold.

Weigh Your Gold

You will need to know how much your gold weighs. Gold is sold and weighed in troy ounces. Jewellers and gold buyers use two different calculations, pennyweights (DWT) and grams (G) The value of your gold will be exactly the same regardless of what weighing method is used. Pennyweights (dwt): there are 20 pennyweights in one troy ounce Grams (g): there are 31.1 grams in one troy ounce Grams to pennyweight conversion: 1.555 grams per pennyweight Example: 23.7g / 1.555 = 15.24dwt.

Spot Price of Gold

The spot price of gold is the price it is selling for at any given time. Since the spot price is changing constantly you will need to know the current spot price of gold to determine the value of your scrap gold. For the example below we will assume the gold price is $1300 per troy ounce.

Calculate the Value of 9ct Gold

We will use 9ct gold as our example on how to calculate actual gold content and its value. We have assumed the price of gold per troy ounce is $1300 AUD.

a.  Your 9ct yellow gold chain weighs 4.3 grams which is 2.76 pennyweights (dwt).
b. 2.76 dwt x .375% = 1.035 pennyweight pure gold
c. Spot gold price of $1400.00 / 20 pennyweight per oz. = $70.00 per pennyweight.
d. 1.035 dwt x $70.00 = $72.45 (the actual pure gold content value of the chain).

Another example is...
So, we have a scrap gold chain that weighs 24.2 pennyweights. It is 9ct so there is 37.5% pure gold in the chain. We took 24.2 pennyweights and multiplied it by .375% to get the weight of the pure gold. That equates to 9.074 pennyweights of pure gold. There are 20 pennyweights in one troy ounce. Spot gold is selling for $1300.00 per troy ounce. We divided $1300.00 by 20 to get a pure gold value of $65.00 per pennyweight. We then multiplied 9.075 pennyweights of pure gold times $65 per pennyweight and we get $589.81.

Remember to use the correct currency when calculating the value of your gold. Many online spot prices are in USD. You can use this method to calculate the value of any gold carat/purity.