Gold Karat Calculator

Translate stamped purity marks into actual gold percentages in seconds. Pick a standard karat rating or punch in a three-digit European millesimal number to see how pure your metal really is.

Toss in your scale reading, and the tool strips out alloy metals to calculate your true pure-gold weight. It's the fastest way to make sense of foreign hallmarks like 585 (14K) or 750 (18K) on estate rings, bullion coins, and scrap lots before you ever step up to a dealer's counter.

Convert Gold Karat, Fineness and Purity

Choose a karat grade or millesimal stamp number. If you have a scale handy, enter the weight to see the piece's exact purity and pure gold yield.

How the Gold Karat Calculator Works

This tool translates purity between traditional karats, millesimal fineness codes, and simple percentages. Karats measure metal in 24ths, whereas European fineness systems grade purity on a 1,000-point scale.

Take a standard 14K ring: it’s 58.3% pure gold (commercially standardized to 58.5%) and typically bears a "585" hallmark stamped inside the band. Drop your scale weight into the tool, and it strips away base alloy metals to give you your exact pure-gold yield.

Conversion formulas:

• Purity percentage = Karat ÷ 24 × 100

• Fineness = Purity percentage × 10

• Pure gold weight = Item weight × Purity percentage

Gold Karat to Fineness Conversion Chart

Gold Karat Calculator FAQs:

What does gold karat mean?

Karats grade gold on a simple 24-point scale. Pure, unalloyed gold is 24K. A typical 14K wedding band contains 14 parts pure gold mixed with 10 parts alloy metals like copper, silver, or zinc to give the piece real-world durability.

What is gold fineness?

Fineness is the European metric equivalent of a karat rating, measuring metal purity out of 1,000 parts rather than 24. A piece marked 585 contains 585 parts pure gold per thousand, meaning it is 58.5% pure metal.

Is 585 gold the same as 14K gold?

Yes. In the jewelry trade, 585 and 14K refer to the same tier of gold. Strict math puts 14 parts out of 24 at 58.33% purity, but international mints and jewelers universally round up to 585 (58.5%) as the official commercial hallmark.

Can the calculator identify an unmarked piece?

No. The calculator only crunches figures you already know. If an old piece has no hallmark or the stamp wore away over decades of use, don't guess—take it to a bench jeweler or coin shop for a quick scratch or XRF scan to verify the alloy.

Disclaimer:

These numbers are rough melt estimates to guide your research, not guaranteed cash offers. Hallmarks can be faked, misread, or stamped onto plated base metal. Always have an unmarked piece or family heirloom tested in person by a reputable coin dealer or bench jeweler before closing a deal.