Gold Purity Converter
Convert gold purity between karats, percentage, and millesimal fineness (hallmark numbers). Interactive conversion and full reference table.
Enter any one value and the other two will be calculated automatically.
Quick Reference
Click any row to populate the converter.
Complete Gold Purity Reference Table
| Karat | Parts Gold | Purity % | Millesimal Fineness | Common Uses |
|---|---|---|---|---|
| 24K | 24/24 | 99.9% | 999 | Bullion, Coins, Pure gold items |
| 22K | 22/24 | 91.6% | 916 | Coins, Jewellery (durable) |
| 20K | 20/24 | 83.3% | 833 | Mid-tier jewellery |
| 18K | 18/24 | 75% | 750 | Diamond / gemstone jewellery |
| 16K | 16/24 | 66.7% | 667 | Less common |
| 14K | 14/24 | 58.3% | 583 | Western jewellery, rings |
| 12K | 12/24 | 50% | 500 | Alloys, decorative |
| 10K | 10/24 | 41.7% | 417 | US minimum legal "gold" |
Understanding Gold Purity
Gold purity is described in karats in India. Pure gold is defined as 24 karats. Each karat represents one twenty-fourth part. So 22 karat gold contains 22 parts of gold and 2 parts of other metals.
What is Millesimal Fineness?
Millesimal fineness is the number stamped on gold jewellery and bullion as a hallmark. It represents parts per thousand. 916 means 916 parts per 1000 are pure gold, which equals 22K. Look for this number on hallmarked BIS jewellery in India.
BIS Hallmarking in India
The Bureau of Indian Standards (BIS) requires gold jewellery sold in India to carry a hallmark indicating its purity. The hallmark consists of the BIS logo, the fineness number (916, 750, etc.), the assaying centre mark, and the year of marking.