Calculate Gold Alloy Percentage
Find the percentage that is not gold.
The alloy percentage is the remainder after the gold percentage is removed. It does not identify the exact metals used in the alloy.
What Is Gold Alloy Percentage?
Gold jewellery and other gold products can contain gold mixed with other metals. Karat expresses how much of the alloy is gold, while the remainder is the non-gold portion.
For 18K gold, the gold percentage is 75%, so the non-gold portion is 25%.
Gold Alloy Percentage by Karat
| Karat | Gold % | Non-Gold Alloy % |
|---|---|---|
| 24K | 100% | 0% |
| 22K | 91.67% | 8.33% |
| 21K | 87.50% | 12.50% |
| 18K | 75% | 25% |
| 14K | 58.33% | 41.67% |
| 10K | 41.67% | 58.33% |
| 9K | 37.50% | 62.50% |
18K Gold Alloy Percentage
18K gold is 75% gold on the 24-part scale.
Thus, 18K represents 75% gold and 25% non-gold material in the mathematical purity calculation.
22K Gold Alloy Percentage
22K gold is approximately 91.67% gold.
14K Gold Alloy Percentage
14K gold is approximately 58.33% gold.
Does Alloy Percentage Identify the Alloy Metals?
No. A purity calculation tells you the total non-gold proportion, but it does not identify which metals or elements make up that portion.
The actual alloy recipe can vary according to the manufacturer, colour of gold, manufacturing requirements and applicable standards.
Alloy Percentage and Jewellery Weight
For an existing alloy weight, the non-gold mass can be estimated by multiplying the alloy weight by the non-gold fraction.
For example, 20 grams of 18K gold contains approximately 25% non-gold alloy, or 5 grams.
Important Limitations
This calculator calculates a composition percentage from a stated purity value. It does not identify the actual chemical composition of an unknown item.
Frequently Asked Questions
What is the alloy percentage in gold?
It is the non-gold portion remaining after the gold percentage is removed from 100%.
What is the non-gold percentage in 18K gold?
18K is 75% gold, so its mathematical non-gold portion is 25%.
What is the non-gold percentage in 22K gold?
22K is approximately 91.67% gold, leaving approximately 8.33% non-gold alloy.
What is the alloy percentage in 14K gold?
14K is approximately 58.33% gold, leaving approximately 41.67% non-gold alloy.
How is non-gold alloy percentage calculated?
Subtract gold percentage from 100%.
Does the alloy percentage identify the exact metals?
No. It only describes the total non-gold portion.
Does this calculator determine jewellery value?
No. It calculates composition percentages only.