Convert karats to gold hallmarks (kt to hallmark) and gold hallmarks to karats (hallmark to kt) Online Conversion Calculator - Converter

This calculator-converter provides conversion of karats to millesimal fineness gold hallmarks (kt to hallmark) and backwards millesimal fineness gold hallmarks to karats (hallmark to kt).

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Conversion Chart / Table
 karat to gold hallmarks Conversion Chart / Table: gold hallmarks to karats Conversion Chart / Table: kt = hallmark 6 = 250 8 = 333 9 = 375 10 = 417 12 = 500 14 = 583 karat = gold hallmarks 15  = 625 18  = 750 20  = 833 21  = 875 22  = 916 24  = 999 or higher hallmark = kt 250 = 6 333 = 8 375 = 9 417 = 10 500 = 12 583 = 14 gold hallmarks = karats 625 = 15 750 = 18 833 = 20 875 = 21 916  = 22 999 or higher  = 24

The karat (kt) (outside of US and Canada spelling: carat, abbreviation: ct) is a measure of the purity of gold or platinum alloys. Carat purity is measured as 24 times the purity by mass. Carat rating = 24 * mass of pure gold in the alloy / total mass of the alloy. Therefore, 24 carat rating is a pure pure gold or platinum.
24 karat gold (kt) = 999 gold hallmark (millesimal fineness hallmark) or better, which is close to 100% pure gold. 12-carat gold = 500 millesimal gold fineness hallmark = 50% gold.