Gold Purity Guide — Understanding 9ct, 14ct, 18ct, 22ct & 24ct Gold

Gold purity is one of the biggest factors in how much you'll be paid for your jewellery, coins, or scrap gold — often more important than weight alone. This guide explains what each carat means, how to spot it on your items, and how it translates into what we'll pay you.

What Is Gold Purity?

Gold purity is measured in carats (ct) in the UK, or sometimes as a "fineness" number (like 375 or 999). Pure gold is soft and impractical for everyday jewellery, so it's almost always mixed with other metals — silver, copper, or palladium — to add strength and durability. The carat number tells you what proportion of the item is actual gold.

24 carat is the maximum — 100% pure gold. Everything below that is an alloy, with the percentage of real gold decreasing as the carat number drops.

Gold Purity Breakdown

24ct Gold (99.9% Pure)
The purest form of gold available, used almost exclusively for bullion bars, investment coins (like Britannias and Krugerrands), and some Asian jewellery styles. 24ct gold is very soft and scratches easily, which is why it's rarely used for rings or everyday-wear jewellery in the UK. Because it's essentially pure, 24ct items carry the highest value per gram of any purity.

22ct Gold (91.6% Pure)
Common in Asian bridal and ceremonial jewellery, and used in some gold coins. 22ct strikes a balance between high gold content and slightly improved durability over 24ct, though it's still relatively soft compared to lower carats. Its high purity means it holds strong resale value, close behind 24ct.

18ct Gold (75% Pure)
The standard for premium jewellery in the UK and Europe — engagement rings, quality watches, and higher-end pieces are typically 18ct. It offers a richer, warmer colour than lower carats while being noticeably more durable than 22ct or 24ct. 18ct sits in a strong middle ground for resale value.

14ct Gold (58.3% Pure)
Popular in the US and increasingly common in the UK, 14ct balances affordability, durability and gold content. It's a practical choice for everyday-wear jewellery and holds solid resale value, though less than 18ct gram-for-gram.

9ct Gold (37.5% Pure)
The most common gold purity in UK jewellery, largely because it's more affordable and highly durable — ideal for rings and chains that see daily wear. Because it contains the least actual gold of the standard carats, 9ct has the lowest value per gram, but it still holds genuine resale value and is worth having tested rather than discarded.

How to Spot Purity: Hallmarks and Stamps

UK gold jewellery is usually stamped with a small number indicating its fineness. These are the ones you'll most commonly see:

Look for this stamp on the inside of rings, the clasp of chains and bracelets, or near the fastening of bangles — it's often very small and may need a loupe or magnifying glass to read clearly. UK items sold since 1973 legally require hallmarking above a certain weight threshold, alongside a maker's mark and an assay office mark (a small symbol showing which UK assay office tested the piece).

How Purity Affects Your Payout

Your valuation comes down to three things:

• Purity (carat) — how much actual gold is in the item
• Weight — measured precisely in grams
• The live gold price per gram at the time of testing

As a rough example: a 10-gram 9ct item and a 10-gram 18ct item weigh the same, but the 18ct piece contains roughly double the actual gold — so it's worth roughly double, even though they look similar in size. Curious exactly how we determine this? See how we test and value your gold.

Not sure what carat your gold is? Check today's price per gram for every carat and use our calculator to estimate your item's value.

How We Determine Purity

We use XRF (X-ray fluorescence) analysis to test every item, which identifies exact purity without cutting, scratching, or damaging your gold. This is more reliable than reading a stamp alone, since stamps can wear away, be inaccurate on older or foreign pieces, or in rare cases be counterfeit.

Want to check for yourself first? See our guides on telling gold from gold-plated and spotting fake or counterfeit gold.

FAQs

Is 9ct gold worth selling?
Yes. While 9ct contains less gold than higher carats, it still has genuine resale value, and prices are currently strong. Many people assume low-carat jewellery isn't worth testing — it's usually worth more than expected, especially in weightier pieces like chains or bangles.

Do you buy mixed-purity items?
Yes. Items with multiple metals or components — such as a ring with a gold band and non-gold stones — are tested individually so you're paid accurately for the actual gold content, not the item's total weight.

Can purity stamps be trusted?
Usually, but not always. Stamps can wear down over time, and older, antique, or non-UK items sometimes carry markings that don't match UK conventions. That's why we test every item with XRF analysis regardless of what's stamped on it, so your valuation reflects the item's true purity.

Why does 18ct look different from 9ct or 24ct?
Colour varies with the alloy metals used, not just the gold content. 9ct can appear paler or slightly more yellow depending on the alloy mix, while 24ct has a deep, rich yellow since it's unalloyed. This is a rough visual guide only — testing is the only reliable way to confirm purity.

Ready to find out what your own items are worth? Read our full guide on how to sell gold by post.

Check your gold purity and get the best price — order your free postal gold kit.