Gold Calculator
Enter the weight, karat and the current gold spot price to see the melt value, the pure gold content and what a buyer might pay.
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Enter the weight, the karat and today’s gold spot price to get the melt value of gold jewelry, coins or scrap.
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How to calculate the value of gold
The melt value of gold depends on three things: its weight, its purity (karat) and the spot price of gold. Pure gold is 24 karat. Jewelry is usually alloyed with other metals, so 18K gold is 18/24 = 75% gold, and 14K is 14/24 = 58.3%. To find the value, convert the weight to grams, multiply by the purity, convert to troy ounces (1 troy ounce = 31.1035 grams) and multiply by the gold price per ounce.
Karat and purity
| Karat | Purity | Typical use |
|---|---|---|
| 24K | 99.9% | Bullion bars and coins |
| 22K | 91.7% | Indian jewelry, some coins |
| 18K | 75.0% | Fine jewelry |
| 14K | 58.3% | Common US jewelry |
| 10K | 41.7% | Lowest US legal karat |
| 9K | 37.5% | UK and European jewelry |
Worked example
A 10 g piece of 18K gold when the spot price is $2,400 per troy ounce: pure gold = 10 × 0.75 = 7.5 g = 0.2411 troy oz. Melt value = 0.2411 × $2,400 = about $578.71. Buyers usually pay 70% to 95% of melt value depending on the type of buyer, so the payout would be about $492 at 85%.
Weight units for gold
| Unit | Grams |
|---|---|
| 1 troy ounce | 31.1035 g |
| 1 pennyweight (dwt) | 1.5552 g |
| 1 gram | 0.03215 troy oz |
| 1 ounce (avoirdupois, regular) | 28.3495 g |
Tips when selling gold
- Check the stamp: 750 means 18K, 585 means 14K, 416 means 10K, 999 means 24K.
- Weigh the piece without stones, which are not gold; stones add weight but no melt value.
- Compare several buyers and ask for the percentage of melt value they pay.
- The spot price changes every day, so check the current price before you sell.
This calculator uses the spot price you enter; it does not pull live prices. For live gold prices in euros, see MetalMap. Related tools: percentage calculator and ratio calculator.
How to use the gold calculator
- Enter the weight and choose the unit.
- Select the karat and type today’s gold spot price per troy ounce.
- Read the melt value, pure gold content and the estimated buyer payout.
Frequently asked questions
How do I calculate the value of gold?
Convert the weight to grams, multiply by the karat divided by 24, convert to troy ounces (÷ 31.1035) and multiply by the gold spot price per ounce.
How much is 18K gold worth per gram?
At a spot price of $2,400 per ounce, pure gold is about $77.16 per gram, so 18K (75%) is about $57.87 per gram before any buyer discount.
What is the difference between a troy ounce and a regular ounce?
A troy ounce is 31.1035 grams; a regular (avoirdupois) ounce is 28.3495 grams. Gold is always priced per troy ounce.
Why does a buyer pay less than the melt value?
Buyers cover refining costs, risk and profit, so they typically pay a percentage of the melt value, often between 70% and 95%.
What does the number stamped on gold mean?
It shows purity: 750 = 18K, 585 = 14K, 417 = 10K, 999 = 24K.
Related tools: Percentage calculator · Ratio calculator · Unit converter