The formula
Weight in grams × purity ÷ 31.1035 × gold spot per troy ounce = melt value. Karat converts to purity by dividing by 24; a 14K mark commonly uses the trade fineness 0.5833 or 0.585.
Worked 14K example
A 21.3-gram 14K chain contains about 12.42 grams of pure gold: 21.3 × 0.5833. At the fallback $4,043.70/ozt price, that is about $1,615.26 in melt value before any buyer discount.
Gold value by karat
| Karat or fineness | Pure gold | Fallback value per gram |
|---|---|---|
| 24K — pure (.999) | 99.90% | $129.88/g |
| 22K (.9167) | 91.67% | $119.18/g |
| 21.6K — old US coins (.900) | 90.00% | $117.01/g |
| 18K (.750) | 75.00% | $97.51/g |
| 14K (14/24 = .5833) | 58.33% | $75.83/g |
| 585 gold (.585) | 58.50% | $76.05/g |
| 12K (.500) | 50.00% | $65.00/g |
| 10K (.417) | 41.67% | $54.17/g |
| 9K (.375) | 37.50% | $48.75/g |
| 8K (.333) | 33.30% | $43.29/g |
What the formula excludes
Subtract stones and non-gold parts from weight. The formula does not appraise craftsmanship, brand, condition, rarity, or collector value; those can put an item's market value above melt. A buyer may pay below melt for testing, refining, and margin.
Run the live gold calculator with your own weight, purity, and price.
Frequently asked questions
What is the formula for gold melt value?
Multiply gold weight by its purity, divide grams by 31.1035 to get troy ounces, and multiply by the live gold price per troy ounce.
Is melt value what a gold buyer will pay?
Usually not. Melt value is the contained-metal benchmark; buyer costs and margin reduce most scrap offers, while collectible or branded value can increase resale value.
How do I convert karat to purity?
Divide karat by 24. For trade calculations, use the stamped fineness when known, such as 0.585 for many 14K pieces or 0.750 for 18K.