How GoldOfferCheck calculates gold value
Every estimate uses a visible formula. You can edit the reference gold price and compare the result with a real buyer offer.
The core formula
Net gold weight is the entered total weight after subtracting any separately entered non-gold weight. The tool estimates metal value only; it does not appraise craftsmanship, rarity, gemstones, brand value, collectability, taxes, shipping, or refining costs.
Purity factors
| Mark | Factor used | Approximate gold content |
|---|---|---|
| 10K / 417 | 0.417 | 41.7% |
| 14K / 585 | 0.585 | 58.5% |
| 18K / 750 | 0.750 | 75.0% |
| 22K / 916 | 0.916 | 91.6% |
| 24K / 999 | 0.999 | 99.9% |
Weight conversions
- 1 troy ounce = 31.1034768 grams
- 1 pennyweight = 1.55517384 grams
- 1 avoirdupois ounce = 28.349523125 grams
Reference gold price
The calculator attempts to retrieve a current XAU/USD reference from Gold API. The browser caches the result briefly to reduce repeated requests. If that source is unavailable, the calculator displays a clearly editable fallback reference. Always confirm the reference price and timestamp before making a sale decision.
How offer percentages are described
The offer percentage is calculated as buyer offer divided by estimated melt value. Descriptions such as “large discount,” “compare more offers,” and “closer to melt” are comparison aids, not universal judgments of fairness. Buyer costs and local markets vary.
Important limitations
- Hallmarks can be missing, worn, altered, or counterfeit.
- Plated, filled, hollow, soldered, or mixed-metal items need additional testing.
- Do not remove stones or components unless a qualified professional advises it.
- Reference prices and third-party data can be delayed or inaccurate.
- This is an educational estimate, not a professional appraisal or purchase offer.
Methodology reviewed August 26, 2026.