Understanding Karat Ratings and Gold Purity
Karat measures the proportion of pure gold within an alloy. Twenty-four karat (24K) represents 99.9% pure gold—the highest standard. Each karat step down equals approximately 4.17% loss in purity.
Common alloy ratios include:
- 24K — 99.9% pure (unmixed)
- 22K — 91.67% pure (popular for coins and bullion)
- 18K — 75% pure (standard for fine jewellery)
- 14K — 58.33% pure (durable, US jewellery standard)
- 10K — 41.67% pure (the minimum legal standard for "gold")
Lower karats contain base metals like copper, silver, or nickel, which add durability and reduce cost. When calculating scrap value, only the pure gold content matters—the alloy metals have negligible resale worth.
The Gold Melt Value Formula
Calculate the intrinsic value of your gold by multiplying its weight, purity fraction, and the current spot price per unit mass:
Melt Value = Weight × (Purity ÷ 100) × Market Price
Bid Price = Melt Value × (100 − Spread) ÷ 100
Ask Price = Melt Value × (100 + Spread) ÷ 100
Weight— Mass of your gold item (grams, troy ounces, or any unit, as long as you match the price quote unit)Purity— Percentage of pure gold in the alloy (derived from karat rating)Market Price— Current spot price of gold per unit mass (check commodity exchanges for live quotes)Spread— Bid-ask margin as a percentage, representing dealer markup or commission
How to Use the Calculator
Step 1: Enter the karat or custom purity. Select your gold's karat rating from the dropdown (24K, 22K, 18K, 14K, etc.), and the calculator auto-fills its purity percentage. If you know the exact fineness, use the custom purity option.
Step 2: Input the weight. Provide the mass of your gold item. Ensure you're measuring in a unit that matches your price quote (grams, troy ounces, etc.).
Step 3: Set the market price. Enter the current spot price of gold. Check financial websites or commodity brokers for real-time rates, typically quoted per troy ounce.
Step 4: Account for spread (optional). If you want to see what a dealer would actually pay you (bid) or charge you (ask), enter the spread percentage. Typical spreads range from 5% to 15%, depending on the buyer's margin.
The calculator displays your gold's possession value and, if a spread is entered, both the bid and ask prices.
Key Considerations When Valuing Gold
Avoid common mistakes when assessing your gold's worth.
- Weight unit must match price quote — If you quote gold at $2,000 per troy ounce, weigh your item in troy ounces (or convert grams: 1 troy ounce ≈ 31.1 grams). Mixing units is the most frequent source of error.
- Spot price fluctuates constantly — Gold trades 24/5 in global markets. The price you see online may differ by the time you reach a dealer. Lock in quotes quickly if you're planning to sell, or check intraday trends if timing is flexible.
- Dealers always buy below spot — The bid price (what you receive when selling) is always lower than spot due to refining, assay, and handling costs. Don't expect to get 100% of the melt value; typical payouts are 85–95% of calculated worth.
- Numismatic value often exceeds melt value — Rare or collectible coins may be worth far more to coin dealers than their gold content alone. Before melting, have specialist appraisers evaluate historical or rarity premiums.
Why Melt Value Matters
Melt value sets the floor price for gold items. Jewellers, pawnbrokers, and refiners use it to establish fair offers when you sell gold jewellery, coins, or scrap. Understanding the calculation prevents you from accepting lowball bids.
For buyers, melt value helps determine whether purchasing vintage or recycled gold jewellery offers value compared to making a new piece. Retailers typically sell at a markup of 20–50% above melt value, depending on craftsmanship and brand.
Investors in bullion and coins also track melt value to monitor whether they're acquiring gold at a premium or discount to its raw material worth. During market downturns, some coins trade below melt value, creating arbitrage opportunities for those with refining connections.