Karat Converter

Convert Gold Purity Instantly

Switch between karat, millesimal fineness, and percentage purity. The essential reference tool for jewelers, gold buyers, and precious metals investors worldwide.

⏱️ Reading Time: 6 min📅 Updated: August 7, 2026
Karat ↔ MillesimalCustom ValuesFree & Instant

Conversion Result

Enter a value to convert
Karat (K)
Millesimal (‰)
Percentage (%)

Visual Purity Comparison

24K
22K
18K
14K
10K
9K

Height proportional to gold purity percentage

Features

Why Use This Karat Converter

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Three-Way Conversion

Karat, millesimal, and percentage in any direction.

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All Common Purities

Presets for every standard gold purity worldwide.

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Custom Values

Enter any karat, millesimal, or percentage value.

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Visual Scale

See gold content differences proportionally.

Reference

Complete Karat Conversion Table

KaratMillesimal (‰)Percentage (%)Gold Parts/24Common Name
24K999 / 999.999.9%24/24Fine Gold
22K91691.6%22/24Crown Gold
21K87587.5%21/24
18K75075.0%18/24Standard Gold
14K58558.3%14/24Jewelry Gold
10K41741.7%10/24Minimum US Gold
9K37537.5%9/24Minimum UK Gold
8K33333.3%8/24Low Gold
Methodology

Conversion Formulas

Karat ÷ 24 × 1000 = Millesimal  |  Millesimal ÷ 1000 × 24 = Karat
K→M:18K = 18÷24×1000 = 750
M→K:585 = 585÷1000×24 ≈ 14K
K→%:14K = 14÷24×100 = 58.33%
Common Questions

Frequently Asked Questions

585 = 14K gold. 585 parts per thousand pure gold (58.5%). European standard marking. Older pieces may show 583.

Yes. 750 (millesimal) = 18K (karat) = 75% pure gold. Different systems, identical purity.

Divide karat by 24, multiply by 100. 14K = 14÷24×100 = 58.33%. 18K = 75%. 22K = 91.67%.

Ancient Roman system: 24 parts = pure gold. 24 divides evenly by 2,3,4,6,8,12 making alloys easy to express.

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