Gold melt value equals weight in troy ounces multiplied by gold purity multiplied by the gold spot price. If you are estimating a real offer, multiply that result by the buyer payout percentage.
The formula
Start with the item weight. Convert that weight to troy ounces because gold spot price is quoted per troy ounce.
Multiply by purity. 24K is nearly pure gold, 18K is 18/24 or 75%, 14K is 14/24 or 58.33%, and 10K is 10/24 or 41.67%.
Multiply by the spot price. The result is metal melt value before any buyer discount, refining fee, shipping, or assay adjustment.
Example
A 10 gram 14K item contains about 10 / 31.1034768 x 14 / 24 = 0.1875 troy ounces of pure gold.
If spot gold is $4,000 per troy ounce, melt value is about 0.1875 x $4,000 = $750.
If a dealer pays 90% of melt, the estimated offer would be about $675.
What melt value excludes
Melt value ignores diamonds, gemstones, brand, craftsmanship, rarity, and collector demand.
It also ignores non-gold parts such as stones, steel springs, watch movements, filled knife handles, and solder.
Common questions
Why do gold calculators use troy ounces?
Gold spot price is quoted per troy ounce, so gram, pennyweight, and regular-ounce weights must be converted before multiplying by spot price.
Should I sell gold for melt value?
Melt value is a baseline, not a required sale price. Collectible coins, designer jewelry, or pieces with stones can be worth more outside the scrap channel.