18k Gold Calculator
18k gold calculator for 750 jewelry and scrap from weight and spot. See three-quarter purity melt value in grams or DWT before you take a live cash offer.
Gold Value Calculator
Current 18K price · —/gram · —/tola
Using live market spot for this calculation.
Formula: weight × karat multiplier × spot price. 18K = 0.750
Eighteen-karat pieces feel heavier in the hand — and in the payout — than the 10K and 14K that fill most U.S. drawers. Miss the stamp and you leave a fat slice of fine gold priced like cheaper alloy.
The reverse bites too. Someone waves an "18K look" at you with no 750 mark, and a soft quote based on color alone is how you overpay or over-expect.
This tool fixes purity at 75% (18 ÷ 24) so your weight and spot talk 18K, not a neighbor karat.
Reading 750 at the bench
18K and 750 mean the same fineness story: three-quarters gold by weight in solid alloy. You'll see both marks on European and higher-end U.S. jewelry.
Solder seams and repairs can assay differently than the stamped shank. If a piece looks heavily repaired, treat the calculator result as a starting line — assay still wins.
Gold-filled or vermeil with a flashy color is not 18K. If the mark says GF, stop.
Dial the estimate in five moves
- Confirm 18K / 750 on each piece you care about.
- Separate 14K and 22K so they don't share one average.
- Weigh without loose stones when you can pull them.
- Enter grams or DWT — whatever the scale shows.
- Read the melt-style total, then ask what % of melt the buyer is offering.
Under-plumb habits matter more as karat climbs. If your shop regularly assays light on certain makers, shade the scenario down or read half karat under plumb.
18K purity table
| Measure | Figure |
|---|---|
| Karat | 18K |
| Purity | 75% (18 ÷ 24) |
| Common mark | 750 |
| Pure gold in 10 g of 18K | 7.5 g |
| Pure gold in 1 troy oz of 18K jewelry | 0.75 troy oz fine |
Value ≈ weight × 0.75 × gold price (matched units).
EXAMPLE — bracelet at $4,000 / oz
EXAMPLE spot: $4,000 / troy oz (illustrative).
Pure gram ≈ 4000 ÷ 31.1035 ≈ $128.60.
18K gram ≈ 128.60 × 0.75 ≈ $96.45.
Confirmed 18K bracelet, 12 g, clean:
Fine gold = 12 × 0.75 = 9 g
Melt-style ≈ 9 × 128.60 ≈ $1,157.
Same bracelet wrongly run as 14K (0.583) understates by roughly 22%. That's a real negotiation gap, not a rounding error.
Where 18K scrap usually sits
Clean Italian chains and classic bands sometimes clear jewelry resale above melt. Broken links, mismatched earrings, and scrap cuttings track refining math.
Ask whether the buyer's "18K rate" is per gram of jewelry or per fine gram. Write their answer on the ticket. Memory fails under fluorescent lights.
For the broader formula walk-through, see how to calculate gold value.
Related tools and guides
- Goldcalculator
- all gold calculators
- 14K gold calculator
- 22K gold calculator
- gold karat calculator
- gold jewelry calculator
- gold purity hallmark chart
Frequently Asked Questions
How pure is 18K gold?
75% gold by weight in solid alloy (18 ÷ 24). Hallmark 750 matches that fineness.
Is 18K always worth more per gram than 14K?
Per gram of jewelry, yes at the same spot — more fine gold in each gram. Per piece, weight and condition still decide the cash.
Can I use this for 18K scrap filings?
Yes if the filings are confirmed 18K bench waste. Mixed karat dust needs assay. See bench filings gold value.
Why might assay come in under 750?
Repairs, solder, and under-plumb manufacture. Budget a cushion when history says pieces run light.
Does 18K plated count?
No. Plate and filled layers are not solid 750 alloy. Use the gold filled calculator for GF marks.
Grams or DWT for 18K?
Either. Match your scale. 1 DWT ≈ 1.55517 g. Purity stays 0.75.
Disclaimer
Assumes solid 18K at 75% unless you enter another scenario. Settlement follows assay and buyer terms. Educational estimates only.