Metal value
Gold Melt Value Calculator
Estimate the metal-only value of gold from its weight, fineness and a gold price you enter. Gemstones, design and resale value are not included.
Open toolFree tools
Free jewelry tools
Search common fineness marks or estimate metal-only melt value from inputs you provide. These tools do not authenticate or appraise jewelry.
Marks and materials
Jewelry Hallmark Quick Reference
Search common jewelry fineness marks and see what the numbers can mean. A stamp is a clue to research, not proof of authenticity or metal content.
Open toolSizing
Ring Size Converter (US, UK, EU, Japan, mm)
Convert a ring size between US, UK letters, EU/ISO, Japanese sizes and inner diameter in mm. Includes a size chart. Free, in your browser.
Open toolGemstones
Diamond MM to Carat Calculator (All Shapes)
Estimate a diamond’s carat weight from its length, width and depth in mm for round, oval, princess, pear and more. An estimate, not a weighing.
Open toolGemstones
Carat to MM Converter (Round Diamond Size)
See the approximate diameter of a round brilliant diamond for any carat weight, with a size chart from 0.25 to 3 carats. Free, in your browser.
Open toolMetal value
Silver Melt Value Calculator
Estimate the metal-only value of sterling (925), fine (999) or coin (900) silver from weight and a price you enter. No live price feed.
Open toolMetal value
Platinum Melt Value Calculator
Estimate the metal-only value of platinum jewelry (950, 900, 850) from its weight and a price you enter. Stones and design are not included.
Open toolMetal value
Gold Karat to Purity Converter (K, ‰, %)
Convert gold karat to fineness (parts per thousand) and percent, or back. See the matching hallmark, e.g. 14K = 585. Free, in your browser.
Open toolSizing
Necklace Length Guide and Calculator
Find the style name for a chain length (choker, princess, matinee, opera, rope) and how far it hangs below your neck. In inches or cm. Free.
Open toolSizing
Bracelet Size Calculator (Wrist to Length)
Turn your wrist measurement into a bracelet length for a snug, comfort or loose fit, in cm or inches. Free and in your browser.
Open toolThese utilities explain the inputs they use and the limits of their results. A photo, stamp or calculation cannot certify a piece or replace an in-person professional examination.