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Gold Purity Calculator

Convert karats (24K, 22K, 18K, 14K, 10K, 9K) to fineness and millesimal hallmarks, and calculate the pure gold content and value of any piece.

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Fineness

750 / 1000

75% gold by mass

Pure gold in 5.00 g: 3.75 g · worth $500.04

KaratHallmarkGold by massPrice per gram (USD)
24K fine999.999.99%$133.33
24K99999.90%$133.21
22K91691.67%$122.24
21K87587.50%$116.68
18K75075.00%$100.01
14K58558.33%$77.78
10K41741.67%$55.56
9K37537.50%$50.00

Based on the reference gold price $4,147.50 per troy ounce (live spot).

Karat, fineness and hallmarks

Karat expresses purity in 24ths: 24K is pure gold, 18K is 18/24 = 75%, 14K is 58.3%. Millesimal fineness expresses the same thing in parts per thousand, which is what hallmarks show: 750 for 18K, 585 for 14K, 375 for 9K. Bullion is typically 999 or 999.9.

The pure-gold content of a piece is its weight × fineness; multiply by the price per gram of pure gold to get the metal value.

Results are informational and exclude dealer premiums, fees and taxes. Disclaimer · Methodology

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