How to convert 12K gold to 9K
12K gold is 50.0% pure and 9K gold is 37.5% pure. To find the 9K weight with the same gold content, multiply the 12K weight by 0.5 and divide by 0.375. One gram of 12K equals 1.3333 grams of 9K.
Example
10 g of 12K gold contains 5 g of pure gold, the same as 13.3333 g of 9K. Today 10 g of 12K is worth $665.59.
When you need this conversion
- Exchanging old jewelry for new pieces in a different karat.
- Comparing prices quoted per gram of 22k with prices quoted for 18k or 24k.
- Planning how much of a karat a jeweler needs to remake an item.
Note that remaking jewelry involves melting losses and labor, so a jeweler's exchange rate is usually below this pure-gold equivalent. See methodology.