Trade tools
Everyday calculations for the bench, the office and the trade fair floor. Free to use, built by people in the trade.
Sizes and conversions
Ring size converter
US, UK, EU, Japanese and Swiss sizes, diameter and circumference.
Trade weight unit converter
Grams, troy ounces, pennyweight, tola, baht, tael, momme and more.
Wire and sheet gauge converter
AWG / B&S and British SWG gauges in millimetres, with weight per metre.
Standard jewellery sizes
Necklace and chain lengths, bracelets, Indian bangle sizes and earring posts.
Metals
Gold karat & fineness converter
Karat to fineness and back, pure gold content, hallmarks by country.
Scrap and melt value calculator
Spot value of the gold, silver, platinum or palladium in a piece, in 18 currencies.
Metal weight calculator
Wire, sheet, tube or a ring band, in any common alloy.
Casting weight calculator
From wax or resin model weight to metal needed per alloy.
Hallmarking by country
Compulsory or voluntary, legal fineness standards and weight exemptions in 34 countries.
Plating and compliance standards
Gold filled, vermeil and plate rules; nickel, lead and cadmium limits.
Alloying calculator
Fine metal and alloy for a new karat, a karat change or scrap, checked against tolerance