Scrap Gold Calculator

How to use this scrap gold calculator

What this calculator does. It estimates how much pure gold is contained in a scrap item and multiplies that fine-gold weight by a quoted price. It is useful for screening jewelry, coins, dental gold, or manufacturing offcuts before requesting a dealer offer. It does not determine authenticity, assay results, collectible value, gemstone value, or the net cash a buyer will actually pay.

When to use it. Use it to compare offers quoted in different weight units, check the effect of a karat stamp, convert a market price per troy ounce into an implied price per gram, or estimate the gross value of a batch before refining. For legal-for-trade transactions, weighing and testing practices may be regulated; NIST explains recognized precious-metals weight and conversion practices.

How to calculate. The calculator opens with a complete demonstration: 120 grams of 18K gold, 75% purity, and a $70 per gram quote. The example workbook is ready immediately. (1) Replace Weight of scrap gold and choose grams, troy ounces, or pennyweight. (2) Enter either Gold purity by karat or Gold purity by percent; the paired field updates automatically. (3) Enter Price per unit weight and choose the price unit. (4) Read the total and breakdown, then select Download Excel to save the current model. Reset clears the demonstration values and may disable export until all required fields are valid again.

Input guide. Weight of scrap gold is required, accepts a positive decimal, and can be entered in g, troy oz, or dwt; for example, 120 g. More weight increases value proportionally. Do not confuse a regular avoirdupois ounce with a troy ounce: NIST gives one troy ounce as exactly 31.1034768 grams. Gold purity by karat is required from 0 through 24; 18 is a realistic jewelry example and raises value as it approaches 24. A stamp is not a laboratory assay. Gold purity by percent is the same purity on a 0 – 100 scale; 75 means 75%, not 0.75. Editing it updates karat using percent × 24 ÷ 100. The FTC explains that 18K gold contains 18 parts gold out of 24. Price per unit weight is required and must be a positive USD quote in the selected unit; for example, $70/g. Use the same basis as the chosen price unit and avoid entering a dealer's total offer as a unit price.

Output guide. Total value is the estimated gross melt value in U.S. dollars. Pure gold weight is the fine-gold mass shown in the selected scrap-weight unit. Purity is the exact karat-to-percent relationship used. Price per gram normalizes any selected quote to a common basis. Alloy weight is the remaining non-gold mass. The table separates pure gold, other metals, and total scrap; only the pure-gold row receives value in this simplified model. Zero purity produces zero value, while higher weight, purity, or price increases value linearly.

Worked example. With 120 g and 18K purity, the purity fraction is 18 ÷ 24 = 0.75. Pure gold weight is 120 × 0.75 = 90 g. At $70 per gram, gross value is 90 × $70 = $6,300.00. The remaining alloy weight is 30 g. These figures match the startup controls, summary cards, table, and Excel workbook.

Learn more. Market benchmarks are typically quoted per fine troy ounce. The LBMA Gold Price overview explains the benchmark structure. Convert the quote carefully, then treat this result as a planning estimate rather than a guaranteed purchase offer.