Calculate fine-gold content for 24K, 22K, 18K, 14K, 10K and 9K gold. Enter the weight of gold jewellery, bullion or another gold-alloy item, select the karat, and calculate its purity, fineness, fine-gold weight and non-gold alloy content.
Choose a karat and calculate the actual fine-gold content.
Fine-gold content is calculated from the entered gross gold-alloy weight and the selected karat. Gemstones and other non-gold components are not automatically removed from the entered weight.
The karat system expresses gold purity on a 24-part scale. A karat value tells you how many of those 24 parts are gold. The remainder represents other metals in the alloy.
For example, 18K gold contains 18 parts gold out of 24. That equals 75% gold, or 750 fineness.
24K is the highest karat designation on the traditional 24-part scale. Mathematically, 24K represents 100% gold on that scale. Commercial fine gold is commonly specified using fineness values such as 999 or 999.9.
If 10 grams of material is treated as 24K under the mathematical karat system, the calculated fine-gold content is 10 grams.
22K gold contains 22 parts gold out of 24. This gives approximately 91.67% gold and a mathematical fineness of 916.67.
For 10 grams of 22K gold alloy, the calculated fine-gold content is approximately 9.1667 grams.
18K gold contains 18 parts gold out of 24. It corresponds to 75% gold and 750 fineness.
For 10 grams of 18K gold alloy, the calculated fine-gold content is 7.5 grams.
14K gold contains 14 parts gold out of 24. Its mathematical purity is approximately 58.33%, corresponding to approximately 583.33 fineness.
For 10 grams of 14K gold alloy, the calculated fine-gold content is approximately 5.8333 grams.
10K gold contains 10 parts gold out of 24. Its mathematical purity is approximately 41.67%, corresponding to approximately 416.67 fineness.
For 10 grams of 10K gold alloy, the calculated fine-gold content is approximately 4.1667 grams.
9K gold contains 9 parts gold out of 24. That equals 37.5% gold and corresponds to 375 fineness.
For 10 grams of 9K gold alloy, the calculated fine-gold content is 3.75 grams.
Karat, percentage and fineness describe gold content using different scales. They can therefore be converted mathematically without knowing the current gold price.
| Karat | Gold Purity | Mathematical Fineness | Fine Gold in 10 g Alloy |
|---|---|---|---|
| 24K | 100% | 1000 | 10.0000 g |
| 22K | 91.67% | 916.67 | 9.1667 g |
| 18K | 75% | 750 | 7.5000 g |
| 14K | 58.33% | 583.33 | 5.8333 g |
| 10K | 41.67% | 416.67 | 4.1667 g |
| 9K | 37.50% | 375 | 3.7500 g |
To estimate fine-gold content, first determine the weight of the gold alloy and then apply the karat fraction.
For example, if a piece contains 20 grams of 18K gold alloy:
The remaining 5 grams represents the non-gold portion of the 18K alloy.
The calculator assumes that the entered weight represents the gold-alloy material being evaluated. A jewellery scale, however, may measure the entire finished item.
If a ring contains gemstones, for example, the total scale weight can include the stones as well as the gold. Applying the karat percentage to the entire gross weight can therefore overestimate fine-gold content.
A higher karat generally means a higher proportion of gold in the alloy, but karat alone does not determine the selling price of a jewellery item.
Gold price, weight, workmanship, gemstones, design, condition, taxes, premiums and market demand can all affect the final price.
This calculator is designed to determine gold content rather than provide a complete jewellery appraisal.
Fineness expresses gold content per 1,000 parts. For example, 750 fineness means 750 parts per 1,000 are gold, corresponding to 18K.
Common relationships include 18K = 750, 22K ≈ 916.67 and 14K ≈ 583.33. Commercial markings may use rounded or standardized values.
This calculator performs mathematical calculations from a selected karat and entered weight. It does not test metal composition.
A jewellery hallmark or karat stamp can provide useful information, but a mathematical calculator cannot confirm whether a physical item actually meets that specification.
For an unknown or disputed item, appropriate professional testing or assay information should be used to establish actual composition.
It calculates purity percentage, fineness, fine-gold weight and non-gold alloy content for 24K, 22K, 18K, 14K, 10K and 9K gold.
22K is 22 parts gold out of 24, or approximately 91.67% gold and 916.67 fineness.
18K is 18 parts gold out of 24, equal to 75% gold or 750 fineness.
14K is approximately 58.33% gold and approximately 583.33 fineness.
10K contains approximately 41.67% gold and approximately 416.67 fineness.
9K contains 37.5% gold and corresponds to 375 fineness.
24K represents 24 parts gold out of 24. Commercial fine-gold products are commonly specified using fineness such as 999 or 999.9.
No. It calculates gold content from weight and karat. Gold price, workmanship, gemstones, design, taxes and other factors can affect jewellery value.
No. The calculator interprets a stated karat value but cannot authenticate a physical item.