Free calculators and unit converters for general and everyday use.
Our online tools will provide quick answers to your calculation and conversion needs. On this page, you can calculate purity of gold alloys and percentage of gold indicated by the carat (karat) rating.
A 24 karat gold is considered 100% pure gold.
For gemstones (e.g., diamond) and pearls, carat is a unit of mass equal to 200 mg. Use our Weight conversion tool to calculate the weight of gemstone for given carat value.