About the Gold-Filled & Plated Content Calculator
This calculator estimates the pure gold content — and melt value — of items that are not solid gold. For gold-filled and rolled gold plate, the stamp tells you the gold layer’s share of the total weight (for example “1/20 12K GF” means one-twentieth of the metal is 12-karat gold). For vermeil and electroplated items, gold content depends on the plating thickness and the surface area, so you enter those instead.
It is for anyone sorting a jewelry box, an estate lot or a scrap pile and wondering whether gold-filled watch cases, chains or plated pieces are worth sending to a refiner. It also shows why gold-filled items usually hold far more gold than plated ones, and why plated items rarely have meaningful scrap value.
Under the US FTC Jewelry Guides, gold-filled must carry a gold layer of at least 1/20 of the article’s metal weight, electroplated gold plate needs at least 0.175 microns of 10K-or-better gold (2.5 microns for “heavy gold electroplate”), and vermeil needs at least 2.5 microns of 10K-or-better gold over sterling silver. Refiners pay only a fraction of melt value for low-content material.
With the default inputs, the pure gold content is 0.75 g. Change any value above to recalculate instantly.
How to use the gold-filled & plated content calculator
- 1Choose gold-filled, vermeil or gold plated.
- 2Weigh the item in grams (remove stones, springs and non-metal parts).
- 3For gold-filled, pick the fraction and karat from the stamp, e.g. 1/20 and 12K.
- 4For plated or vermeil, estimate the gold-covered surface area and plating thickness.
- 5Enter spot prices to see pure gold content and melt value.
Formula and method
A gold-filled stamp such as “1/20 12K GF” states that the gold-alloy layer is 1/N of the article’s total metal weight and that the layer is K karat. Pure gold is therefore the item weight divided by N, multiplied by K ÷ 24. A 1/20 12K item is 1/20 × 12/24 = 2.5% pure gold; 1/20 14K is 2.92%.
Plated and vermeil items are not rated by weight, so the layer mass is estimated from geometry: surface area (cm²) × thickness (µm converted to cm by × 10⁻⁴) × the alloy’s density. Typical yellow-gold densities are used: 24K 19.32, 22K 17.8, 18K 15.6, 14K 13.1, 12K 12.3 and 10K 11.6 g/cm³. For vermeil the remaining weight is valued as 92.5% silver (sterling). Melt value converts grams to troy ounces (31.1034768 g) and multiplies by spot.
- W
- Item weight in grams
- N
- Fraction denominator from the stamp (20 for 1/20)
- K
- Karat of the gold layer
- A, t, ρ
- Surface area (cm²), thickness (µm) and alloy density (g/cm³)
Worked examples
30 g of 1/20 12K gold-filled
The 12K layer is 1/20 of 30 g = 1.5 g, and 12K is half gold, so the item contains 0.75 g of pure gold — 2.5% of its weight. At $4,000/oz that gold is worth about $96 at full melt.
20 g vermeil pendant, 10 cm² at 2.5 µm of 10K
10 cm² × 0.00025 cm × 11.6 g/cm³ gives a 0.029 g gold layer, of which 10/24 is pure gold: about 12 mg, worth $1.55. The 19.97 g sterling base holds 18.47 g of silver, worth about $28.51 at $48/oz — most of the value is the silver.
Gold-plated cufflinks: 5 cm² of 24K at 0.5 µm
5 cm² × 0.00005 cm × 19.32 g/cm³ = 4.8 mg of pure gold, worth about 62 cents at $4,000/oz. This is why plated items have essentially no scrap gold value.
Frequently asked questions
What does 1/20 12K GF mean?+
It means the gold layer is 1/20 (5%) of the item’s total metal weight and that layer is 12-karat gold (50% pure). So the item is 2.5% pure gold by weight — 0.25 g of gold for every 10 g of item.
Is gold-filled worth anything as scrap?+
Yes, but far less than solid gold. A 1/20 14K item contains about 2.9% pure gold, and refiners often pay a reduced percentage of melt for gold-filled because refining the base metal is costly. Large lots are worth more per gram than single pieces.
What is the difference between gold-filled and gold-plated?+
Gold-filled has a thick, mechanically bonded layer that must be at least 1/20 of the metal weight in the US. Gold electroplate is a thin film that legally needs only 0.175 microns of 10K-or-better gold, so it holds a tiny fraction of the gold that gold-filled does.
What is rolled gold plate?+
Rolled gold plate is made the same way as gold-filled but with a thinner layer — less than 1/20 of the weight, and at least 1/40 under the FTC Guides. It is marked with its fraction and karat, for example “1/40 10K RGP”.
What is vermeil?+
Under US FTC rules, vermeil is sterling silver coated with at least 2.5 microns of gold or gold alloy of 10 karat or higher. Its scrap value comes mostly from the sterling silver base rather than the gold.
How do I estimate surface area for a plated item?+
Break the item into simple shapes. A flat piece is about 2 × length × width; a ring band is roughly circumference × band width × 2 (inside and outside). Small errors matter little because plating holds so little gold.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.