How Gold Prices Are Calculated: From Spot Price to Price per Gram
Every gold calculator starts from one number: the spot price of gold per troy ounce, quoted in US dollars. Everything else — price per gram, per tola, per karat, in your own currency — is arithmetic on top of it.
Published by the Heartline Works team · Last reviewed 2026-10-02 · Editorial policy
Step 1: the spot price
The spot price is the benchmark price for immediate delivery of one troy ounce of pure (99.9%+) gold, quoted in US dollars. Data providers publish it continuously while global markets are open. It is a reference, not a price anyone is obliged to sell you gold at.
Step 2: from ounces to grams
A troy ounce is 31.1034768 grams. Dividing the ounce price by that number gives the price of one gram of pure gold.
| Quantity | Formula |
|---|---|
| Price per gram (pure) | spot per troy ounce ÷ 31.1034768 |
| Price per 10 g | price per gram × 10 |
| Price per tola | price per gram × 11.6638038 |
| Price per kilogram | price per gram × 1000 |
Step 3: adjust for purity
Jewelry is rarely pure gold. Karat tells you the share of gold by weight, out of 24 parts. Multiply the pure-gold price by the purity factor: 22K is 22 ÷ 24 = 0.9167, 18K is 0.75, 14K is about 0.5833.
Step 4: convert the currency
The result is multiplied by the exchange rate from US dollars to your currency. Because exchange rates and gold prices are published separately, both need to be recent for the answer to be meaningful — which is why the calculators on this site show the time of each.
What the result is, and is not
The output is a reference metal value. A jeweller’s selling price adds making charges, wastage, taxes and margin; a buyer’s offer deducts a margin and often a refining cost. Local markets also move on local supply and demand. See the guide on spot price versus local price for how large those differences can be and why.
Try the tools
- Gold Price Calculator — Gold price per gram, 10 grams, tola, troy ounce and kilogram for any karat, in your currency.
- Gold Value Calculator — Reference value of gold by weight and purity, with pure-gold content.