10K vs 14K gold: what the difference means when you sell

What karat means

Karat measures the share of pure gold in a piece, out of 24 parts. Pure gold is 24 karat. Under the Federal Trade Commission’s jewelry guides (16 CFR Part 23), the word “gold” on its own means fine, 24 karat gold, and gold alloy, anything under 24 karat, should carry a correct karat designation before the word, as in “14 Kt. gold”. The guides also say 14 karat should not be described as “solid gold”.

So the gold share of any piece is simply its karat divided by 24.

Pure gold share by karat

Karat	Calculation	Pure gold share
10K	10 / 24	41.7%
14K	14 / 24	58.3%
18K	18 / 24	75%
22K	22 / 24	91.7%
24K	24 / 24	100%

What 14K means

14K gold is 14 parts gold to 10 parts other metals, so 58.3% of its weight is pure gold. A 14K piece is gold alloy, not “solid gold” in the FTC’s sense, but it is real gold, and more than half of it by weight is pure gold.

What 10K means

10K gold is 10 parts gold to 14 parts other metals, or 41.7% pure gold. Less than half of a 10K piece’s weight is gold. It is still real gold and is priced by its gold content like any other karat.

10K vs 14K gold, side by side

• Gold content. 14K holds 58.3% gold; 10K holds 41.7%. A 14K piece contains about 40% more gold than a 10K piece of the same weight (58.3 divided by 41.7).
• Alloy. The rest of each piece is other metals: 58.3% of a 10K piece, 41.7% of a 14K piece. Those metals add little or nothing to what a buyer pays for gold.
• The stamp. Both should be marked with their karat before the word gold under the FTC guides, so the stamp tells you which one you have.
• Value when you sell. A buyer pays for the pure gold, so at the same weight a 14K piece is worth more than a 10K piece.

How the karat changes what a piece is worth

The value of the gold in a piece is: weight in troy ounces x gold share x the spot price of gold per troy ounce. One troy ounce is 31.10348 grams (NIST SP 811).

Take two chains that each weigh one troy ounce. The 10K chain holds 0.417 troy ounces of pure gold; the 14K chain holds 0.583. If the spot price of gold is X dollars per troy ounce, the gold in the 10K chain is worth 0.417 x X dollars and the gold in the 14K chain 0.583 x X dollars. The spot price changes through every trading day, so check it on the day you sell.

That figure is the melt value, the value of the pure metal only. A buyer’s offer is usually below it because the buyer pays to refine the metal and needs a margin. The page on how to sell gold jewelry explains weighing and comparing offers.

How to read the stamp

Look for the karat inside a ring’s band, on the clasp or the tag beside it on a chain, on the post or back of an earring, and inside a bangle. Common forms are 10K, 10KT, 14K, 14KT and 14 Kt. A loupe or a phone camera on zoom helps with small stamps.

Watch for plated marks. The FTC guides use terms such as “Gold Plate”, “Gold Plated”, “Gold Overlay” and “Rolled Gold Plate” for a layer of gold alloy of at least 10 karat over another metal, with the plating’s karat stated before the term, for example “1/40 12 Kt. R.G.P.”. A plated piece is not solid gold, whatever karat the plating is. The article on how to tell if jewelry is real gold covers this in more detail.

Is 10K gold real gold?

Yes. 10K gold is a gold alloy that is 41.7% pure gold. It is real gold, stamped and sold as gold alloy with its karat. It is worth less per gram than 14K because it holds less gold.

What does 14K mean on a ring?

A 14K stamp inside a ring means the band is 14 karat gold alloy: 58.3% pure gold by weight. If the ring has stones, the stones may be valued separately or deducted from the weight. If the ring has a diamond, see the guide on where to sell diamond jewelry.

Tolerances

The National Stamping Act, cited in the FTC guides, allows gold with no solder to be up to three parts per thousand under its mark, and gold with solder up to seven parts per thousand under. A piece with soldered joints may test slightly under its stamp without anything being wrong.

Questions people ask