Before you begin: obtain a current gold reference price in US dollars per troy ounce and note its source, timestamp and quote type. This tool does not fetch or verify market data.
How the gold calculator works
The calculator converts the entered weight to grams, multiplies it by the purity percentage, converts the chosen troy-ounce price to a price per gram, and multiplies those two figures.
gross grams × (purity ÷ 100) = fine-gold grams reference price per troy ounce ÷ 31.1034768 = reference price per gram fine-gold grams × reference price per gram = reference melt value reference melt value × payout percentage = modeled payoutThe arithmetic can be checked by hand. That transparency matters because a small unit or purity error can materially change the result.
Worked example: a 20 gram 18K ring
Assume the ring's net gold-bearing weight is 20.00 grams, its tested fineness is 75%, and a hypothetical reference price is USD 2,500 per troy ounce.
- Fine gold: 20.00 g × 0.750 = 15.00 g.
- Fine gold in troy ounces: 15.00 ÷ 31.1034768 = about 0.48226 ozt.
- Reference melt value: (15 ÷ 31.1034768) × USD 2,500 = about USD 1,205.65.
That is not a guaranteed offer. It assumes the entire 20 grams is gold-bearing alloy at the stated fineness. A real object may include stones, springs, solder or other material, while a desirable maker or design may add resale value.
Which purity should you enter?
| Mark or description | Calculator entry | Arithmetic basis |
|---|---|---|
| 999.9 fine | 99.99% | 999.9 parts gold per thousand |
| 22K | 91.6667% | 22 divided by 24 |
| 18K or 750 | 75% | 18 divided by 24 |
| 14K | 58.3333% | 14 divided by 24 |
| 10K | 41.6667% | 10 divided by 24 |
| 9K or 375 | 37.5% | 9 divided by 24 |
A mark is evidence, not certainty. National marking rules and tolerances vary, and a plated or altered object may not match its surface. Read the gold purity guide before relying on an unfamiliar stamp.
Which weight should you enter?
Use the net weight of the gold-bearing material whenever it can be established safely. Gross jewelry weight can include gemstones, dirt, steel watch components, springs and other parts. Do not damage an object or remove stones merely to make an online estimate more exact; an appraiser, estate jeweler or specialist buyer may be a better route.
Be especially careful with ordinary ounces and troy ounces. They are separate units. The calculator supports both and converts them independently.
What does payout percentage mean?
The percentage field is a simple way to model a net amount below theoretical melt. For example, 90% models a payment equal to 90% of the calculated reference melt value. It does not prove that 90% is fair for a particular item or buyer.
Actual terms may include fixed assay charges, refining loss, shipping, insurance, commissions or delayed settlement rather than one percentage. A collectible or readily resalable item can also attract a premium above contained-metal value. Ask for a written explanation of the final amount.
What this calculator cannot determine
- Whether a hallmark or purity claim is genuine.
- Whether plating, solder or an unrepresentative surface test distorts the result.
- The value of gemstones, craftsmanship, brand, provenance, rarity or condition.
- A buyer's actual recovery, overhead, risk, margin or payment terms.
- Taxes, legal restrictions or currency-conversion costs in your jurisdiction.
Do not treat the result as an appraisal or binding bid. It is an educational estimate using the inputs you supplied.