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

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

Enter gold hallmarks or karats for conversion:

Select conversion type:

Rounding options:

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

The millesimal fineness gold hallmark system is used to denote the purity of gold, platinum or silver alloys by parts per thousand of pure metal by mass in the alloy. Therefore, an alloy containing 50% gold is denoted as "500", 75% gold = "750" etc. Many European countries use millesimal hallmark stamps rather than karat rating stamps.
999 gold hallmark (millesimal) or better, which is close to 100% pure gold = 24 karat gold (kt). 500 millesimal fineness gold hallmark = 12-karat gold = 50% gold alloy.