What Is Gold Carat (or Gold Karat)?

If you’ve ever shopped for gold jewellery, you’ll have seen terms like 9ct, 18ct or 24k in the description — but what do these numbers actually mean?

Put simply, gold carat (or karat) tells you how pure the gold is. It shows how many parts of pure gold are present out of a total of 24 parts.

Understanding gold carat helps you choose jewellery that suits your lifestyle, budget and colour preference — whether you’re buying a gold ring, necklace or bracelet.

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What Does Gold Carat Mean?

Gold carat measures the purity of gold in an item of jewellery.

• 24 carat gold = 24 parts pure gold (almost 100%)

• 18 carat gold = 18 parts gold, 6 parts other metals

• 9 carat gold = 9 parts gold, 15 parts other metals

The remaining metals are called alloys, commonly copper or silver, which make gold stronger and more suitable for everyday wear.

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Gold Carat vs Gold Karat – Is There a Difference?

No — they mean exactly the same thing.

• Carat (ct) is used in the UK and most of the world

• Karat (k) is used in the USA

So 18ct gold and 18k gold are identical in purity.

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Why Is “Carat” Used for Diamonds Too?

This is where confusion often arises.

• Gold carat refers to purity

• Diamond carat refers to weight

A diamond’s carat weight tells you how heavy it is, not how pure it is. Despite sharing the same spelling, the two measurements are completely unrelated.

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Where Does the Term Carat Come From?

The word carat comes from the carob seed, which was historically used as a counterweight for measuring gemstones and precious metals.

Over time, this system evolved into the 24-carat standard, where pure gold became the benchmark against which all other gold alloys were measured.

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Why Isn’t All Jewellery Made from 24 Carat Gold?

Although 24ct gold is the purest form, it is also:

• Very soft

• Easily scratched or bent

• Less practical for everyday jewellery

By mixing gold with other metals, jewellers create alloys that are stronger, more durable and more affordable, while still retaining gold’s beauty.

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Common Gold Carat Types Explained

24 Carat Gold (24ct / 24k)

• 99.9% pure gold

• Very soft

• Rich yellow colour

• Rarely used for everyday jewellery

22 Carat Gold (22ct / 22k)

• 91.7% pure gold

• Rich colour

• Often used for traditional or ceremonial jewellery

18 Carat Gold (18ct / 18k)

• 75% pure gold

• Excellent balance of beauty and durability

• Commonly used for wedding and engagement rings

14 Carat Gold (14ct / 14k)

• 58.5% pure gold

• Strong and practical

• More common in the USA than the UK

9 Carat Gold (9ct)

• 37.5% pure gold

• Very durable

• Ideal for everyday jewellery

• Lighter colour and more affordable

Many people choose 9ct gold for rings with gemstones or jewellery worn daily, as it is harder and more resistant to wear.

👉 View our Gold Jewellery Collection here.

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Gold Carat Comparison Table

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What Is Millesimal Fineness?

In the UK, gold purity is also shown using millesimal fineness, which appears as part of the hallmark.

This shows how many parts of pure gold are present out of 1000:

• 18ct gold → stamped 750

• 22ct gold → stamped 916 or 917

• 9ct gold → stamped 375

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Does Gold Carat Affect Colour?

Yes. The higher the carat, the richer the yellow colour.

Gold alloys also affect colour:

• Rose gold contains more copper. This is what is distinctive about Welsh Gold.

• White gold uses lighter metals and is usually rhodium plated

• Yellow gold retains gold’s natural warmth

All colours of gold can be made in different carats.

👉 Related read: What Is White Gold?

👉 Related read: What does Gold Filled Mean?

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FAQs – Gold Carat Explained

What is the best gold carat for everyday jewellery?

For daily wear, 9ct or 18ct gold are the most practical choices due to their durability.

Is 18 carat gold better than 9 carat gold?

It depends on preference. 18ct gold contains more gold and has a richer colour, while 9ct gold is harder and more affordable.

Does higher carat gold hold its value better?

Higher carat gold contains more pure gold, which can increase intrinsic value, but condition and craftsmanship also matter.

Is 9 carat gold real gold?

Yes. In the UK, 9ct gold is legally recognised as gold jewellery.

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In Summary

Gold carat (or karat) tells you how much pure gold is in a piece of jewellery. Once you understand the differences, it becomes much easier to choose gold jewellery that fits your lifestyle, budget and personal taste.

Whether you prefer the rich warmth of 18ct gold or the durability of 9ct gold, knowing the carat value ensures you know exactly what you’re buying.