Enter the total weight and the Karat of the gold into the calculator to determine the weight of the pure gold. You can also enter the total dollar amount the gold was purchased for to determine how much was paid per ounce of pure gold.

Gold Weight Formula

The following formula is used to calculate the weight of gold given the karat and the total weight of the metal. 

GW = TW * K / 24
  • Where GW is the pure gold weight (ounces or grams)
  • TW is the total weight of the gold metal piece (ounces or grams)
  • K is the karat of the gold metal piece

Gold Weight Definition

Gold weight is defined as the actual weight of the pure gold in a piece of gold since most gold is not 100% pure gold and contains other metals and impurities.

How to calculate gold weight?

Example Problem #1:

First, determine the weight of the total gold/metal piece. For this problem, the total piece of gold is measured to be 400 grams.

Next, determine the Karat of the gold. This is also known as the purity of the gold on a scale of 1 to 24, with 24 be 99.99% pure or higher.

In this case, the gold is determined to be a 10 karat gold piece.

Finally, calculate the weight of just the gold in the specimen using the formula above:

GW = TW * K / 24

= 400 * 10/24

= 166.66 grams of pure gold.

Example Problem #2:

In this next example, the weight of the specimen is 300 grams and the purity of the gold is 15 Karats.

Using the formula as we did above:

GW = TW * K / 24

= 300 * 15/24

= 187.5

In this case, even though the total weight was less, the gold weight was more because the specimen was of higher purity.