Short answer: price per gram = (gold price per troy ounce in dollars ÷ 31.1035) × karat purity × the dollar exchange rate in your currency. With this simple formula you can check the real metal value of gold at any time and compare it with shop prices. If you just want the result, our pages for Egypt, Saudi Arabia, the UAE and every major currency calculate it automatically.
Step 1: Start from the world price per ounce
Gold is priced worldwide in US dollars per troy ounce. A troy ounce is 31.1035 grams of pure gold. This is the price you hear on the news, and it moves throughout the trading day.
Step 2: Get the price of a gram of pure gold
Divide the ounce price by 31.1035. The result is the dollar price of one gram of 24K (essentially pure) gold.
Step 3: Multiply by the karat purity
The karat tells you how many parts out of 24 are pure gold:
| Karat | Gold content | Multiply by |
|---|---|---|
| 24K | 99.9% | 0.999 |
| 22K | 91.6% | 0.916 |
| 21K | 87.5% | 0.875 |
| 18K | 75% | 0.75 |
| 14K | 58.5% | 0.585 |
Step 4: Convert to your currency
Multiply by the dollar rate in your currency. In Egypt use the USD to EGP rate; in Saudi Arabia the riyal is pegged at about 3.75 per dollar; in the UAE the dirham is pegged at about 3.6725.
A full worked example
These numbers are for illustration only, not current prices. Suppose gold is 3,000 dollars an ounce and the dollar is 50 Egyptian pounds:
- 24K per gram in dollars = 3,000 ÷ 31.1035 ≈ 96.45 dollars.
- 21K per gram in dollars = 96.45 × 0.875 ≈ 84.39 dollars.
- 21K per gram in pounds = 84.39 × 50 ≈ 4,220 pounds.
Notice that the local price moves for two reasons: the world gold price and the local currency against the dollar. If either changes, the price per gram changes.
Why shop prices differ from the calculated value
- Making charges: the cost of turning gold into jewellery, added when you buy.
- Local market premium: when demand is high, local prices can sit slightly above or below the calculated value.
- Buy-back deductions: dealers usually pay a little less than the metal value when you sell, and making charges are not refunded.
- Taxes and hallmarking fees: these vary by country.
Tips before buying or selling
- Work out the metal value with the formula or our gold calculator.
- Ask for the gold price and the making charge separately so you can compare shops.
- Check the hallmark and get an invoice showing the weight and karat.
Frequently asked questions
Why is an ounce of gold 31.1 grams and not 28?
Precious metals use the troy ounce (31.1035 g), which is heavier than the ordinary ounce used for food (about 28.35 g).
Is 21K better than 18K?
21K contains more gold and is worth more per gram; 18K is harder and suits fine or gem-set jewellery. See 21K vs 18K vs 24K gold.
This article is general information, not financial or investment advice. See our methodology and disclaimer.