How KaratWorth Calculates Value
Every KaratWorth result uses standard, published precious-metal math: the same formulas a refiner or appraiser uses. This page documents exactly how each number is produced so you can verify it yourself.
In short
KaratWorth converts your item's weight to grams, multiplies by its purity (karat fraction) to find pure-metal content, converts that to troy ounces, and multiplies by the live spot price. The result is the melt value: the raw metal worth before any dealer fees or making charges.
The core melt-value formula
Worked example: 10 grams of 22K gold at a $2,400/oz spot price:
- Pure gold content = 10 g × 0.916 = 9.16 g
- In troy ounces = 9.16 ÷ 31.1035 = 0.2945 ozt
- Melt value = 0.2945 × $2,400 = $706.80
Karat & purity reference
| Karat | Purity | Fineness |
|---|---|---|
| 24K | 99.9% | 999 |
| 22K | 91.6% | 916 |
| 21K | 87.5% | 875 |
| 18K | 75.0% | 750 |
| 14K | 58.5% | 585 |
| 10K | 41.7% | 417 |
| 9K | 37.5% | 375 |
The purity fraction is simply karat ÷ 24. For 18K that is 18 ÷ 24 = 0.75 (75%). See our gold purity guide for full detail.
Weight unit conversions
All weights are converted to grams first using these factors. Regional units like tola, bhori, and vori vary by market. KaratWorth uses the most common standards and lets you override them.
| Unit | Grams |
|---|---|
| Gram (g) | 1 |
| Kilogram (kg) | 1,000 |
| Troy ounce (ozt) | 31.1035 |
| Regular ounce (oz) | 28.3495 |
| Pennyweight (dwt) | 1.5552 |
| Tola (standard) | 11.6638 |
| Bhori / Vori | 11.6638 |
| Pakistan market tola | 12.5 |
Spot prices
Spot price is the global market price for one troy ounce of pure metal. KaratWorth attempts to load a live spot price automatically; when a live feed is unavailable you can enter the current price manually. Because markets move constantly, always confirm the spot price before relying on a result.
We never fabricate or manipulate prices. If no reliable price is available, the calculator clearly asks you to supply one.
Buyer payout & offer fairness
Dealers pay a percentage of melt value to cover refining and margin. Our scrap and offer tools express any offer as a percentage of melt value so you can judge fairness: most reputable buyers pay roughly 70–90% of melt for gold. These payout ranges are guides, not guarantees.
Results are estimates
KaratWorth results are educational estimates only and depend on the values you enter. Actual quotes vary with market conditions, dealer fees, jewelry condition, taxes, and assay results. For high-value decisions, get independent verification. See our full disclaimer.