Gold karat chart and purity calculator
What each karat means in percent gold and in the hallmark stamped on the piece, and how much pure gold a piece of a given weight holds.
| Karat | Parts gold in 24 | Percent gold | Hallmark |
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Enter a weight to see the pure gold it holds.
Karat is purity out of 24 parts. The rest of the piece is alloy, usually copper, silver or zinc, added because pure gold is soft enough to dent in normal wear. A hallmark is a clue, not proof: stamps can be faked. GP, HGE and GF mean plated or filled, not solid.
What does 585 mean on gold?
A 585 stamp means the piece is 14 karat gold: 58.5% pure gold, with the rest made up of other metals. It is the European way of writing purity, as parts of gold per 1,000. The common stamps are 375 for 9k, 417 for 10k, 585 for 14k, 750 for 18k, 916 for 22k and 999 for 24k. Karat itself is exact arithmetic, 14 parts of 24, which is 58.3%. The stamp rounds that to the 58.5% standard, which is why you will see both numbers for the same piece.
How much gold is in 14k, 18k and 10k gold?
14k gold is 14 parts gold and 10 parts other metals, so it is 58.3% gold. 18k is 75% gold and 25% alloy, and 10k is 41.7% gold. The other metals are usually copper, silver or zinc. They are added on purpose, because pure 24k gold is soft enough to dent in normal wear. More alloy means a harder piece, which is why 14k is the usual choice for jewelry worn every day.
Is a gold stamp proof that a piece is real?
No. A stamp is a first clue, and stamps are easy to fake. Marks such as GP, HGE and GF mean a piece is plated or filled, not solid gold, so the karat number then describes only the thin outer layer. Check the high-contact points for wear, and use a density test rather than a magnet alone. The full set of checks is in how to tell if gold jewelry is real.
The full answer: 14k vs 18k gold for everyday jewelry. All our tools: see the list.
