From 375 to 999: Gold Hallmark Numbers and the Karat vs Fineness Explained
You are in a second-hand jewellery shop. You see a gold ring. You pick it up, turn it over. Inside the band is a tiny stamp that says 750. Or, perhaps, 585. Or 916. No reason given. Just a figure.
They are gold hallmark numbers that are used to denote the quality of gold, and knowing what they mean is one of the most practical things you can do before buying, selling, or valuing any piece of gold. Whether you’ve inherited jewellery, are comparing gold coins, or are just curious about what you already have, this guide tells you exactly what those stamps mean.
Quick Answer
Gold stamps like 750, 585, and 916 are millesimal fineness numbers. They indicate the parts of pure gold per 1,000. So 750 means 750 parts gold out of 1,000, which equals 75% purity, the same as 18-karat gold. The number on your gold tells you its purity level and directly affects its value.
What Is the Difference Between Karat and Fineness?
When people talk about karat vs fineness gold, they are describing the same thing in two different systems.
Karat is the older, more familiar system used mainly in the UK, USA, and parts of Asia. It measures gold purity on a scale of 24, where 24 karats equal pure gold.
Millesimal fineness (also called gold millesimal fineness) is the European and international standard. It expresses purity as parts per 1,000. A piece stamped 750 contains 750 parts gold per 1,000, which is 75% pure.
Both systems measure the same thing. The stamp on your jewellery just depends on where and when it was made.
Gold Karat Chart: Full Comparison of Stamps, Purity, and Common Uses
This table covers every stamp you are likely to encounter, from low-purity everyday jewellery to investment-grade bullion.
| Karat | Fineness Stamp | Gold Purity % | Common Use |
|---|---|---|---|
| 9K | 375 | 37.5% | Affordable jewellery (UK, Australia) |
| 10K | 417 | 41.7% | Budget jewellery (USA, Canada) |
| 14K | 585 | 58.5% | Popular jewellery worldwide |
| 18K | 750 | 75.0% | Fine jewellery, luxury watches |
| 22K | 916 | 91.6% | Traditional jewellery, gold coins |
| 24K | 999 | 99.9% | Bullion bars, investment coins |
Once you know your gold’s purity from the stamp above, you can use a free gold value calculator to find out exactly what it is worth at today’s live spot price.
Breaking Down the Most Common Gold Purity Stamps
What Does “750” Mean on Gold? (18K Gold Fineness)
This means the piece is 18 karat, 75% gold and 25% other metals, such as copper, silver or zinc. This is one of the most popular purities used in fine jewellery across the globe. It is a good balance of rich colour, durability, and high gold content. If you are in the market for a luxury watch or a quality engagement ring, 750 is the stamp you are most likely to see.
585 Gold Meaning (14K Gold Stamp)
The piece is 14-karat gold, which means it is 58.5% pure gold. This is the most common gold purity stamp in the United States and most of Europe. It is harder and more scratch-resistant than 18K, making it a practical choice for rings and bracelets worn every day. It is also cheaper because of the lower gold content, but it has a good resale value.
916 Gold Meaning (22K Gold Purity)
The piece is 22-karat, with 91.6% pure gold. This purity is the standard for traditional South Asian bridal jewellery and for many sovereign gold coins such as the British Gold Sovereign and South African Krugerrand. At this purity level, gold is relatively soft, which is why 916 jewellery tends to feature simpler, more robust designs rather than fine, detailed settings.
What Is 999 Gold?
It is as close to pure gold as is commercially made. Investment products such as bullion bars, PAMP Suisse wafers and coins, such as the Canadian Maple Leaf, are almost exclusively made of 999 gold, which is 99.9% pure gold. It is too soft for most jewellery as it scratches and bends rather easily with everyday wear.
375 Gold Meaning (9K Gold)
It’s 9-karat, which means it’s only 37.5 percent pure gold. This is the legal minimum to be sold as gold jewellery in the UK and Australia. It is the most durable because it has a higher alloy content. It is the least expensive option. 18k gold is less than half gold by weight. If you’re selling 9K pieces, expect valuations to reflect that lower purity.
Related article: Troy Ounce vs Gram vs Tola: Gold Weight Units Explained
Practical Tips for Reading Gold Stamps
How to read gold stamps correctly comes down to knowing what to look for and where.
- •Location: On rings, the stamp is usually inside the band. On chains and bracelets, check near the clasp. On bars and coins, it is engraved on the face or edge.
- •Magnification: Most hallmarks are tiny. A jeweller’s loupe or even a phone camera zoomed in will help you read them clearly.
- •Multiple stamps: Some pieces carry both the karat mark (e.g. 18K) and the fineness number (750). Others carry only one. Both are valid.
- •Maker’s marks: A hallmark may appear alongside a maker’s mark or assay office symbol. The purity stamp is specifically the three-digit number.
- •No stamp: In older or handmade pieces, stamps may be worn away or absent. An acid test or XRF scan by a jeweller can verify purity.
If you are selling inherited jewellery or comparing pieces before a purchase, knowing the stamp lets you do an informed valuation before you walk into any shop.
Frequently Asked Questions
Can a gold piece have a karat stamp and a fineness stamp at the same time?
Yes, this is common, especially on European and Swiss-made jewellery. A piece might show both “18K” and “750” to confirm the same purity in both systems. Both marks are valid and mean exactly the same thing.
What does a “P” after a karat stamp mean, such as 18KP?
The “P” stands for “plumb,” a North American term meaning the gold content is exactly at or above the stated karat, not fractionally below it. Under US law, jewellery can be stamped as a given karat if it is within half a karat of that mark. The “P” assures the buyer that the piece meets the exact stated purity with no rounding applied.
Why does gold jewellery need other metals mixed in at all?
Pure 24K gold is extremely soft and malleable. On its own, it would scratch, bend, and lose its shape very quickly under normal wear. Alloying gold with metals like copper, silver, or palladium hardens it and can also alter its colour, producing white gold, rose gold, or yellow gold in varying shades.
Does the country of origin affect which stamp system is used?
Yes. The United States and Canada typically use karat markings (10K, 14K, 18K). The United Kingdom, the European Union, and most international bullion markets use millesimal fineness stamps (417, 585, and 750). Some countries use both, and older pieces from the Middle East or Asia may follow regional conventions that differ slightly.
Is higher-karat gold always more valuable?
Higher karat gold contains more pure gold by weight, so the raw metal value is higher. However, finished jewellery value also depends on craftsmanship, brand, gemstones, and condition.