Tool Gold Purity

Gold Purity & Fine Gold Calculator

Calculate nominal fine-gold content using documented precious-metal weight conversions and either karat or millesimal fineness.

Calculate fine-gold content

Examples: 18 for 18K, or select fineness and enter 999.9.
Enter your own reference price. This site does not supply a live quote.

Results

Nominal gold percentage
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Total weight in grams
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Fine gold in grams
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Fine gold in troy ounces
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Theoretical fine-gold value
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Methodology

NIST precious-metals conversion guidance gives one troy ounce as 31.1034768 grams, one pennyweight as 1.55517384 grams, and 480 grains per troy ounce. Karat mode calculates nominal gold fraction as karat divided by 24; fineness mode divides the entered fineness by 1000.

This is a mathematical estimate of nominal fine-gold content, not an assay or jewelry appraisal.

Primary source

NIST: Conversion Factors for Precious Metal Sales

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