Gold Karats Explained: 24K vs 22K vs 21K vs 18K

Gold prices are quoted by karat every day, yet plenty of people buy gold without really knowing what the number means. What does “karat” measure? Why does a gram of 21K cost less than a gram of 24K? And which karat suits saving, and which suits jewellery? Here are gold karats explained in plain language.

What does karat mean?

A karat (K or kt) measures gold’s purity: how much of a piece is pure gold. The system divides the metal into 24 parts:

• 24K means all 24 parts are gold, so it is practically pure.
• 21K means 21 parts out of 24 are gold and the rest are other metals.
• 18K means 18 parts out of 24 are gold.

Other metals such as copper and silver are mixed in because pure gold is very soft. It scratches and bends easily, so an alloy is harder and better for jewellery, and the added metals also shift the colour slightly.

(Don’t confuse karat with carat, the unit of weight for gemstones such as diamonds.)

Gold karat chart

Karat	Pure gold content	Common hallmark	Typical use
24K	about 99.9%	999	Bars and bullion coins
22K	about 91.6%	916	Some gold coins, much jewellery in South Asia
21K	87.5%	875	Jewellery across most of the Arab world
18K	75%	750	Fine jewellery in Europe, gem-set pieces
14K	about 58.5%	585	Everyday jewellery in Europe and the US

The hallmark is the number stamped on the piece: parts of gold per 1,000. So 875 means 875 parts gold in every 1,000, or 87.5%, which is 21K.

Did you know? Truly 100% pure gold is practically impossible to produce, so bars are usually stamped 999 or 999.9, meaning impurities make up no more than one part per thousand, or less.

24K vs 21K gold

• Purity: 24K is practically pure; 21K is 87.5% gold.
• Hardness: 24K is soft and not ideal for daily wear; 21K is harder and holds up better.
• Colour: 24K is a deep orange-yellow; 21K is slightly lighter.
• Use: 24K mostly goes into bars and saving; 21K is the standard for jewellery in Arab markets.
• Price: a gram of 24K costs more because it contains more gold.

18K vs 21K gold

18K contains only 75% gold, so it is cheaper and tougher than 21K. It’s popular for pieces set with gemstones because it holds stones more securely, and it can be made in white or rose tones depending on the added metals. 21K contains more gold, has a deeper yellow colour and keeps more of its value when resold.

How to work out the price of any karat

Because price follows pure gold content, you can estimate it yourself:

Price per gram of a karat = price per gram of 24K × (karat ÷ 24)

For example, if 24K costs 100 per gram:

• 22K ≈ 100 × 22 ÷ 24 ≈ 91.7
• 21K = 100 × 21 ÷ 24 = 87.5
• 18K = 100 × 18 ÷ 24 = 75

That’s the raw gold value only. Jewellery prices usually add a making charge (the cost of crafting) and sometimes taxes, which is why the same weight can cost different amounts in different shops. Gold also moves every day with world markets and exchange rates, so check the quoted price on the day you buy.

Tips before buying gold

• Check the hallmark and ask for a receipt that states karat and weight.
• Compare making charges: they often vary more between shops than the gold price itself.
• For saving, many people prefer bars and coins because their making charges are lower than jewellery’s. This is general information, not investment advice.
• Buy from reputable, licensed dealers and be wary of deals that look far below market price.

Frequently asked questions

Is 21K or 18K better?

It depends on your goal. 21K has more gold and holds more value; 18K is cheaper, stronger and better for delicate or stone-set pieces.

What does 875 stamped on gold mean?

It means 21K: 875 parts out of every 1,000 are pure gold (87.5%).

Can 24K gold be used for rings and bracelets?

It can, but it’s very soft and bends and scratches easily, so it’s mostly used for bars and coins.

Why does the gold price differ between countries?

The world price is set in US dollars, then each country’s price is affected by its exchange rate, taxes, duties and making charges.

Does 18K gold change colour?

Its colour is stable, though lighter than 21K, and it can be yellow, white or rose depending on the metals added.

Key takeaway

Karat is the number of parts of pure gold out of 24: 24K ≈ 99.9%, 21K = 87.5%, 18K = 75%. The higher the karat, the purer, pricier and softer the gold. To estimate the price of any karat, multiply the 24K price by (karat ÷ 24), then add the making charge. For the bigger picture on what drives prices, see what is inflation.