Gold Karats Explained: 24K, 22K, 21K, 18K and 14K Compared

A karat measures how much pure gold a piece contains out of 24 parts. 24K is practically pure gold (about 99.9%), and the lower the karat, the more other metals are mixed in, so the price per gram falls and the piece gets harder. That is why 24K is preferred for saving in the form of bars and coins, while 21K or 18K is preferred for jewellery worn every day.

What does gold karat mean?

The karat system divides a piece into 24 equal parts. 21K means 21 of every 24 parts are pure gold, or 87.5%, and the other three parts are different metals. A parallel system expresses purity in parts per thousand, so 21K is written 875 and 18K is written 750, and you may find that number engraved on the piece as part of the hallmark.

Jewellery is rarely sold in fully pure gold, because pure gold is a very soft metal that deforms easily when worn or pressed. Metals such as copper, silver and zinc (and sometimes palladium or nickel in white gold) are added to give it strength and the desired colour.

Karat table: purity and common use

Colour and durability: what changes as the karat falls?

Colour. 24K is a deep, warm yellow, and as the karat falls the colour becomes slightly lighter depending on the metals added. More copper gives a reddish tone known as rose gold, and white metals with a special plating give white gold. So 18K may be the same yellow as 21K or a different shade, depending on the alloy.

Durability. The more metals added, the harder the piece. 24K is soft and shows scratches and bends; 22K and 21K are balanced; 18K and 14K withstand friction better and hold gemstones securely. This hardness is why designers lean towards lower karats for gem-set jewellery.

Sensitivity. Some people's skin reacts to certain metals in the alloy, such as nickel. That depends on the alloy recipe, not on the karat alone. If you are sensitive, ask the seller which metals were used.

How do you calculate the price of any karat from the 24K price?

The rule is simple: karat price = 24K price per gram × (karat ÷ 24).

For example, if the price of a gram of 24K is 4,800 Egyptian pounds (an illustrative figure only, not today's price), the approximate values of the other karats are:

To estimate the value of a 10-gram piece in 18K using the same example, the gold in it is worth 10 × 3,600 = 36,000 EGP. If the making charge is 150 EGP per gram (also an illustrative figure), add 1,500 EGP and the approximate total is 37,500 EGP.

Note that this calculation gives you only the value of the pure gold in the piece. The shop's selling price includes the making charge and the dealer's margin, and quoted market prices for each karat may differ slightly from the calculated result depending on the market and on supply and demand. For up-to-date figures see the 21K gold price today in Egypt and the 18K gold price, keeping in mind that displayed prices are indicative and differ from shop to shop.

A practical comparison: 21K versus 18K

Suppose you are comparing two pieces of 10 grams each, and the 24K price per gram is 4,800 EGP (an illustrative example):

• The 21K piece contains 8.75 g of pure gold (10 × 0.875) and is worth 42,000 EGP.
• The 18K piece contains 7.5 g of pure gold (10 × 0.75) and is worth 36,000 EGP.

The difference is 1.25 g of pure gold, or 6,000 EGP. That is the real price of the higher karat, and it explains why you should never compare two pieces by weight alone without looking at the karat. Likewise, if a shop offers you an 18K piece at a price close to that of a 21K piece of the same weight, ask why; the making charge may be the difference.

Yellow, white and rose gold: colour does not tell you the karat

Colour is not an indicator of karat. Yellow, white and rose gold can all be 14K, 18K or 21K; the difference lies in the type of metals mixed in, not in the amount of gold. White gold is made by mixing gold with white metals and is often finished with a bright plating, and the piece may need re-plating after some years. Rose gold contains more copper and turns a warm red. So when buying, read the stated karat rather than judging by the colour of the piece.

Which karat suits you?

For saving and long-term holding: 24K in the form of bars or coins is the usual choice because the making charge is far lower than for jewellery, and its purity is normally documented with a certificate or sealed packaging. For those who prefer saving in jewellery, 21K in Egypt and 22K in the Gulf are the most common.

For daily wear: 21K or 18K balances value and durability: the piece does not deform easily and still holds a large share of gold.

For gem-set jewellery: 18K is the usual choice because it holds stones firmly and tolerates fine shaping.

For budget gifts: 14K gives you a gold piece at a lower price per gram, but its pure-gold content is lower, so keep that in mind when comparing.

Value when reselling

When gold is sold, it is valued mainly on its weight and karat on that day, that is, on the amount of pure gold in it. Little or none of the making charge or design cost is recovered. So a thin piece with a low making charge keeps its relative value better than an ornate piece with a high one. Some dealers may take back pieces they sold on special terms, so ask about the return policy at the time of purchase.

Practical tips before buying

• Keep the invoice, which should show weight, karat, price per gram and making charge separately.
• Make sure there is a clear hallmark on the piece, and read more in how to spot fake gold and read the hallmark.
• Compare at least two shops, and compare the making charge, not just the price per gram.
• Use the gold calculator to estimate the total value before you go to the shop.
• If the piece is for saving, choose the one with the lowest making charge; if it is for adornment, choose what suits your taste and use.

This information is general and educational, not a recommendation to buy or sell, and the figures in the examples are illustrative only.