Gold Karat Chart: Complete UK Guide to Purity, Colour & Value
Whether you're buying gold jewellery, selling inherited pieces, or investing in bullion, understanding gold purity is essential. This chart breaks down every karat level available in the UK — from 8ct right up to 24ct pure gold — with colours, hallmark numbers, durability ratings, and approximate prices per gram.
Quick Reference
Gold purity is measured in karats (ct), out of 24. Divide the karat number by 24 to get the percentage of pure gold. So 18ct = 18/24 = 75% gold. The hallmark fineness number (375, 585, 750, 916, 999) shows parts per thousand. In the UK, 9ct (375) is the legal minimum to be called “gold”.
The Complete Gold Karat Chart
This chart covers every karat level you're likely to encounter in the UK, from 8ct (which cannot legally be sold as “gold” here) up to 24ct pure gold. Use it as a quick reference when buying, selling, or valuing gold.
| Karat | Fineness | Purity % | Gold Content | UK Hallmark | Common Uses | Approx. Price/g |
|---|---|---|---|---|---|---|
| 8ct | 333 | 33.3% | 1/3 gold | Not legal as “gold” | German jewellery imports | ~£22/g |
| 9ct | 375 | 37.5% | 3/8 gold | UK minimum | UK everyday jewellery | ~£26/g |
| 10ct | 417 | 41.7% | 5/12 gold | Rare in UK | US minimum standard | ~£29/g |
| 14ct | 585 | 58.5% | ~3/5 gold | ✓ | European/US fine jewellery | ~£41/g |
| 18ct | 750 | 75.0% | 3/4 gold | ✓ | Luxury jewellery, Rolex | ~£52/g |
| 22ct | 916 | 91.6% | ~11/12 gold | ✓ | Sovereigns, Asian jewellery | ~£64/g |
| 24ct | 999 | 99.9% | Pure gold | ✓ | Bars, Britannias, coins | ~£70/g |
Understanding the Karat System
The karat system measures gold purity on a scale of 24 parts. 24 karat gold is pure gold — all 24 parts are gold, with no other metals mixed in. If an item is 18 karat, then 18 of the 24 parts are gold and the remaining 6 parts are other metals (called alloy metals).
The maths is straightforward: divide the karat number by 24 to get the purity as a decimal. So 18ct = 18 ÷ 24 = 0.75, meaning the item is 75% pure gold. For 9ct: 9 ÷ 24 = 0.375, so it's 37.5% gold.
The remaining percentage is made up of alloy metals — typically copper, silver, zinc, palladium, or nickel. These metals are added deliberately to make the gold harder, change its colour, or reduce cost. Pure gold on its own is extremely soft and would quickly scratch and deform if used for everyday jewellery.
Karat vs Carat: Same Word, Two Meanings
In the UK, we typically spell it “carat” (ct) for both gold purity and gemstone weight — context tells you which is meant. Americans use “karat” (K or kt) specifically for gold purity and “carat” for gemstones. In this guide, we use both spellings interchangeably for gold purity: 18ct = 18K = 18 karat = 75% gold. Don't confuse this with gemstone carats, which measure weight (1 carat = 0.2 grams).
The Fineness System (Hallmark Numbers)
Modern UK hallmarks use millesimal fineness — parts per thousand of pure gold. This is more precise than the karat system and is the international standard used by assay offices. When you see a three-digit number stamped on jewellery (375, 585, 750, 916, 999), that's the fineness.
Gold Colour by Karat
Gold's colour changes dramatically depending on both its karat and the alloy metals used. Here's how yellow, white, and rose gold compare at different purity levels.
The classic gold colour — gets deeper and richer as karat increases
The colour difference between 9ct and 18ct is the most noticeable. Side by side, 9ct looks distinctly paler — sometimes with a slightly greenish cast from the zinc and copper alloys. 18ct and above have the warm, rich gold tone most people associate with “gold colour”.
Gold alloyed with white metals and typically rhodium plated
White gold is made by alloying gold with palladium or a mix of nickel and zinc, then plating the finished piece with rhodium for a bright, silvery-white finish.
When rhodium plated, all karats of white gold look virtually identical — bright and silvery. The key difference is underneath: as the rhodium plating wears off over time, higher karat white gold shows a more yellowish tint, while lower karat white gold stays slightly whiter (due to more white alloy metals). Higher karat white gold needs more frequent rhodium re-plating — typically every 12–18 months for an 18ct ring worn daily, versus every 2–3 years for 9ct.
Gold alloyed with copper for a warm pink tone — increasingly popular since the 2010s
Rose gold gets its pink colour from copper in the alloy. Counterintuitively, lower karat rose gold is pinker because it contains more copper proportionally. A 9ct rose gold piece has about 62.5% alloy (mostly copper), giving it a deep, saturated pink. An 18ct rose gold piece is 75% gold with only 25% alloy, producing a much subtler blush.
Rose gold has surged in popularity since the mid-2010s, driven by fashion trends and brands like Apple (Rose Gold iPhone) and Michael Kors. It's now a staple option for engagement rings, watches, and everyday jewellery alongside yellow and white gold.
Durability by Karat
One of the most important practical considerations when choosing gold is how well it holds up to daily wear. There's a direct trade-off: lower karat gold is harder and more durable, while higher karat gold is softer and more prone to damage.
This happens because the alloy metals mixed with gold (copper, silver, zinc) form a harder crystal structure than pure gold alone. The more alloy, the harder the piece. Pure 24ct gold is so soft you can dent it with a fingernail — which is why it's never used for jewellery that will be worn.
| Karat | Hardness | Scratch Resistance | Tarnish Resistance | Best For |
|---|---|---|---|---|
| 9ct | ★★★★★ Very hard | ★★★★★ Excellent | ★★★★★ Can tarnish | Wedding bands, chains, daily wear |
| 14ct | ★★★★★ Hard | ★★★★★ Very good | ★★★★★ Good | Engagement rings, bracelets |
| 18ct | ★★★★★ Moderate | ★★★★★ Good | ★★★★★ Very good | Fine jewellery, rings with care |
| 22ct | ★★★★★ Soft | ★★★★★ Poor | ★★★★★ Excellent | Occasional wear, coins |
| 24ct | ★★★★★ Very soft | ★★★★★ Very poor | ★★★★★ Will not tarnish | Investment bars and coins only |
Practical Takeaway
For anything you'll wear daily — wedding bands, chains, bracelets that catch on things — 9ct or 14ct is the most practical choice. For rings worn daily with some care, 18ct strikes a good balance. Reserve 22ct for occasional-wear pieces, and 24ct purely for investment bars and coins kept in storage.
Which Karat Is Best For...
The “best” gold karat depends entirely on what you need it for. Here's a decision guide for the most common scenarios.
Wedding bands, chains, daily-wear earrings
Durability matters most for pieces you never take off. Lower karat gold resists scratches, dents, and general wear far better than higher purities.
- ✓ Scratch and dent resistant
- ✓ Affordable to replace if lost
- ✓ Holds up to manual work
- • 9ct is the UK's most popular choice
A special piece that balances beauty and wearability
18ct is the jewellery industry standard for engagement rings. It offers a rich colour, good durability for daily wear, and is perceived as premium.
- ✓ Rich, warm yellow colour
- ✓ Durable enough for daily wear
- ✓ Secure setting for gemstones
- ✓ Generally hypoallergenic
Bars, coins, and bullion for wealth preservation
Maximum gold content means maximum value per gram. Investment gold isn't worn, so softness doesn't matter — only the gold content does.
- • Gold bars (999.9) — lowest premiums over spot
- • Britannias (999.9) — CGT-free, 24ct
- • Sovereigns (916) — CGT-free, 22ct
- • Both UK coins are VAT-free as legal tender
Birthday, anniversary, or milestone presents
18ct gold is perceived as premium without the extreme price tag of 22ct or 24ct. It looks and feels luxurious, making it ideal for meaningful gifts.
- ✓ Perceived as high-quality
- ✓ Beautiful rich colour
- ✓ Wide selection available
- ✓ Good long-term value
Old, broken, or unwanted gold pieces
Dealers buy gold at all purities — 9ct, 14ct, 18ct, 22ct, and 24ct. Your payout is based purely on the weight and purity of your gold at today's market rate. Higher karat pieces are worth more per gram because they contain more gold, but every karat has value. Even damaged, broken, or single earrings are worth selling. Use our free gold calculator to check what your pieces are worth before visiting a dealer.
UK Legal Requirements for Gold
The UK has strict legal standards for gold, governed by the Hallmarking Act 1973. These rules protect consumers by ensuring gold items meet stated purity levels.
Key Legal Points
- •Minimum purity: 9ct (375) is the lowest purity that can legally be described as “gold” in the UK
- •Hallmarking required: Items over 1 gram must be hallmarked by a UK Assay Office before sale
- •Exemption: Items weighing 1 gram or under are exempt from the hallmarking requirement
- •8ct is not “gold”: Items below 9ct cannot legally be sold as gold in the UK, even though they contain gold
The Four UK Assay Offices
Karat and Value: What Your Gold Is Worth
When it comes to selling gold, the karat directly determines the value. Higher karat means more gold per gram, which means a higher payout. But the relationship between karat and retail price is more complex than you might think.
Example: A 15g 18ct gold bracelet when gold is £70/gram:
Scrap value = 15g × £70 × 0.75 = £787.50
The same bracelet in 9ct:
Scrap value = 15g × £70 × 0.375 = £393.75
Dealers typically pay 85–95% of the calculated scrap value to cover refining costs and margin.
There's an important distinction between scrap value and retail value. Scrap value is purely about gold content — weight times purity times price. Retail value includes craftsmanship, brand name, gemstones, and design. An 18ct Cartier ring might cost 10 times its scrap gold value, but when you sell it to a scrap gold dealer, they'll pay based on the metal alone.
The exception is when a piece has collector value or brand premium. Certain vintage pieces, hallmarked antiques, or items from luxury brands (Tiffany, Cartier, Rolex) may be worth significantly more sold as intact pieces rather than scrapped. If you think your gold might have value beyond the metal, get it appraised before selling for scrap.
Check What Your Gold Is Worth Today
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Use the Free Gold CalculatorFrequently Asked Questions
What karat gold is best?
It depends on your purpose. 9ct (375) is best for everyday jewellery — it's the hardest and most durable. 18ct (750) is the standard for luxury jewellery and engagement rings, offering a rich colour with reasonable durability. 24ct (999) is best for investment, where maximum gold content matters and the piece won't be worn.
Is 9ct gold real gold?
Yes. 9ct gold contains 37.5% pure gold, making it absolutely real gold. It is the minimum purity that can legally be sold as “gold” in the United Kingdom under the Hallmarking Act 1973. It's also the most popular gold purity for everyday jewellery in Britain due to its excellent durability and affordability.
Why is 18ct more expensive than 9ct?
18ct gold contains exactly twice as much pure gold per gram as 9ct (75% vs 37.5%). Since the price of gold jewellery is primarily determined by its gold content, 18ct commands roughly double the scrap value of 9ct at the same weight. The retail markup can vary, but the fundamental reason is the doubled gold content.
Can you tell the difference between 9ct and 18ct by looking?
Yes, especially when placed side by side. 18ct yellow gold has a richer, warmer, deeper yellow colour. 9ct yellow gold appears noticeably paler and lighter, sometimes with a faint greenish tint from the zinc in its alloy. The difference is less obvious with white gold (both are rhodium plated to look silvery) or when pieces are viewed in isolation rather than side by side.
Does higher karat gold tarnish less?
Yes, but there's a catch. Higher karat gold is less likely to tarnish because it contains fewer reactive base metals (copper, zinc, silver) that can oxidise. However, higher karat gold is also more likely to scratch because it's softer. So you're trading one form of wear for another: 24ct gold won't tarnish at all but scratches easily, while 9ct is scratch-resistant but may develop a dull patina over time.
What karat is Rolex gold?
Rolex uses 18ct (750) gold for all their gold watches and jewellery. They produce their own proprietary gold alloys in-house at their foundry in Plan-les-Ouates, Geneva, including their signature “Everose” rose gold (designed to resist fading) and their yellow gold formulations. 18ct provides the ideal balance of a luxurious appearance and the durability needed for high-end watch manufacturing.
Is 24ct gold too soft for a ring?
Yes. 24ct (pure) gold is far too soft for rings or any jewellery that will be worn regularly. It's extremely malleable — you can dent it with a fingernail, and normal daily activities will quickly cause scratches, dings, and deformation. This is precisely why jewellers alloy gold with harder metals. For rings, 9ct to 18ct is recommended depending on how often you'll wear the piece.
Find Out What Your Gold Is Worth
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Related Guides
Learn to read hallmarks, identify assay office symbols, and verify your gold's authenticity.
Read Guide →Deep dive into gold purity, alloy chemistry, and how carat affects colour, durability, and price.
Read Guide →Calculate the value of your gold instantly using live UK prices. Supports all karats and weights.
Calculate Now →Sources and References
UK hallmarking standards: The Hallmarking Act 1973. Source:legislation.gov.uk
Assay office information:London Assay Office,Birmingham Assay Office
Gold alloy composition data:World Gold Council
Last updated: March 2026
Founder & Market Researcher
Taro has been actively investing in precious metals and financial markets for over 15 years. Frustrated by the lack of transparent, accurate gold pricing information in the UK, he built London Gold Exchange as a data-driven resource for fellow investors. The site combines real-time market data, verified dealer information from 242+ UK businesses, and insights drawn from years of hands-on experience in the gold market.
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Disclaimer: This guide provides general information about gold karat levels and purity. Approximate prices per gram are illustrative and change with the gold spot price — always check live prices before making buying or selling decisions. For accurate valuations, use our calculator with live prices or consult a professional gold dealer. This content does not constitute financial advice. Information current as of March 2026.
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