When you buy or sell gold, the karat tells you how much of it is pure gold. The rest is other metals, added to make jewellery harder and longer-lasting. Karat is the single biggest reason two pieces of the same weight can be worth different amounts.
Karat at a glance
| Karat | Pure gold | Hallmark number | Common use |
|---|---|---|---|
| 24K | 99.9% | 999 | Bars, coins and investment gold |
| 22K | 91.67% | 916 | Traditional jewellery in South Asia |
| 21K | 87.5% | 875 | Popular jewellery in the Gulf |
| 18K | 75% | 750 | Diamond and stone-set jewellery |
The hallmark number is the purity in parts per thousand, so 916 means 916 parts in 1,000 are pure gold.
How karat changes the price
The daily rate quoted by markets is usually for 24K gold. To find the gold value of a lower karat, multiply by the karat and divide by 24.
For example, if 24K gold is 300 per gram, then 22K is 300 × 22 ÷ 24 = 275 per gram, 21K is 262.50 per gram, and 18K is 225 per gram.
Why you may be offered less when selling
Jewellers usually deduct a percentage when buying back jewellery, to cover melting, refining and impurities, and making charges you paid when buying are rarely returned. The gold value is the starting point for the conversation, not the final price.
Is higher karat always better?
Not for jewellery you wear every day. 24K gold is very soft and scratches or bends easily. 22K and 21K are a balance of purity and strength, and 18K is strong enough to hold stones securely.
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