PURITY TOOL

Gold Purity & Hallmark Calculator

Turn a hallmark into something useful: karat, fine-gold percentage and live theoretical value in your selected currency.

COMMON MARKS 375 · 417 · 585 · 750 · 916 · 999 From 9K to 24K gold
01
Choose a hallmark Select the fineness stamped on the item.
02
Add a weight Optional, only if you want a total metal value.
Your hallmark result will appear here.
HOW TO READ GOLD MARKS

What a hallmark actually tells you

Gold hallmarks express fineness in parts per thousand. A 750 mark means 750 parts out of 1,000 are fine gold, equal to 75% purity or 18 karat gold.