Gold Fineness Chart: Every Mark From 375 to 999

The complete fineness chart

Every row is the same conversion in both directions: fineness ÷ 1000 = decimal purity, and decimal purity × 24 = karat. So 750 ÷ 1000 = 0.75, and 0.75 × 24 = 18. Once you internalise that, you never need the chart again — though it is quicker to glance at than to compute at a counter.

Why 585 and not 583

Strictly, 14 karat is 14/24 = 58.333%. So why is the European mark 585?

Because a hallmark is a legal guarantee of a *minimum*, and assay tolerances are unforgiving. If a manufacturer alloys to exactly 58.33% and the mix drifts a fraction low in one batch, the piece fails assay and cannot be sold. Alloying slightly over — to 58.5% — buys a safety margin at trivial cost. The same logic produces 916 rather than 916.67 for 22K and 375 rather than exactly 375 for 9K.

You will also meet 583 on older Soviet-era and some Asian pieces, which used the strict fraction rather than the rounded-up European convention. Both are 14K in every practical sense; the difference is under a quarter of a percent and will never change a decision.

The useful takeaway: when a fineness mark sits a whisker above the exact karat fraction, that is a sign of a properly assayed piece, not a discrepancy to worry about.

Three- versus four-digit marks

A four-digit mark — 9999, sometimes written 999.9 — appears almost exclusively on investment-grade bullion. It means 99.99% pure, often called "four nines" in the trade. The Canadian Maple Leaf and the American Buffalo are struck at this standard; most cast and minted bars from recognised refiners are too.

Three-digit 999 means 99.9%, or "three nines," which is the ordinary bullion standard and is what most bars and rounds carry.

The practical difference between them is close to nothing for a seller: 99.9% versus 99.99% is one hundredth of one percent of your metal. It matters to refiners buying industrial quantities and to collectors who care about mint specifications. It should not affect what you accept for a coin.

What *is* worth noticing is the absence of any fineness mark on something claiming to be bullion. Recognised bars and coins are marked. An unmarked bar is not automatically fake, but it does need testing before anyone should pay bullion prices for it.

Marks that look like fineness but aren't

Several stamps are three digits and are not purity claims. Mistaking one for a fineness mark is a genuinely expensive error.

• 925 — sterling silver, not gold. On a gold-coloured item this usually means vermeil: gold plating over sterling. The silver has real value; the gold layer has almost none.

• 1/20 or 1/10 preceding a karat mark — a gold-filled ratio. "1/20 12K GF" means the gold layer is one twentieth of the item's weight, and that layer is 12K. The gold content is roughly 2.5% of total mass, not 50%.

• Three-digit maker codes — some manufacturers stamp a model or design number that reads like a fineness mark. Context helps: a genuine fineness mark usually sits alongside an assay or maker's mark, and it will be one of the standard values in the chart above. A number like 412 or 731 is not a standard fineness and is almost certainly something else.

• Country of origin numerals and date letters in UK hallmarking, which appear near the fineness mark and are not purity.

When a mark is ambiguous, the resolution is a test rather than a guess. An acid kit costs about $15; a jeweler's XRF reading takes seconds and most will do it free.

Turning fineness into value

Fineness is the purity term in the only formula that matters:

grams × (fineness ÷ 1000) × price per gram of pure gold = melt value

Because fineness is already a decimal purity scaled by a thousand, it slots straight in — arguably more cleanly than karat does. A 12 g piece marked 750, at a pure gold price of $143/g:

12 × 0.750 × $143 = $1,287

The same 12 g marked 585: 12 × 0.585 × $143 = $1,004. Marked 375: $643.

That is a $644 spread across three pieces of identical size, determined entirely by a number stamped somewhere you probably need a loupe to read. It is the single highest-value piece of information on any item of gold jewelry, and it is free.

How assay offices verify fineness

In the UK, Ireland and much of Europe, a fineness mark is not the manufacturer's opinion — it is a third-party guarantee. Independent assay offices test the metal and apply their own mark alongside the fineness, and hallmarking is legally required above small weight thresholds.

A full British hallmark carries several elements: the sponsor's mark (who submitted it), the fineness number in a shaped surround indicating the metal, the assay office mark (a leopard's head for London, an anchor for Birmingham, a rose for Sheffield, a castle for Edinburgh), and often a date letter. That combination is strong evidence, and it is why British and European pieces can generally be trusted on their marks.

The United States has no equivalent system. American karat marks are applied by the manufacturer under the National Gold and Silver Stamping Act, which makes misrepresentation illegal but involves no independent testing. The marks are usually accurate, and there is no third party who checked. That difference is worth knowing when you are deciding whether to test a piece before selling it: a hallmarked British 750 needs less scrutiny than an unhallmarked American 18K.

UK hallmarking is overseen by the British Hallmarking Council, which regulates the four assay offices and the marks they apply.

Regional conventions worth recognising

Fineness marks carry geography, and the geography often tells you something about the piece.

916 is overwhelmingly South Asian and Gulf. In India, 22K at 916 fineness is the dominant jewelry standard, and "916 gold" is used as a noun. Pieces are typically higher purity than Western jewelry because gold there functions substantially as savings rather than only as ornament.

875 points to the Middle East, where 21K is a common standard that barely exists elsewhere.

750 is the international fine-jewelry default and appears everywhere, though it dominates in Italy, France and Switzerland.

585 signals German, Eastern European or Scandinavian manufacture. Americans call the same alloy 14K.

375 is distinctly British. 9K is legal as gold in the UK and not in the US, so a 375 piece in an American jewelry box almost always arrived from Britain.

333 is German 8K, which cannot legally be sold as gold in either the US or the UK. It still has real metal value — a third of its mass is gold — but expect confusion at a counter.

Frequently Asked Questions