What does 24 karat gold mean?

24K gold is 99.9% pure gold (millesimal fineness 999). It is the highest purity commonly available and is too soft for most jewelry, so it is mainly used in bullion coins and bars.

What is the most common karat for jewelry?

18K (75% pure) is widely used in fine jewelry globally. In the United States, 14K (58.3% pure) is the most popular because it balances purity with durability.

What is millesimal fineness?

Millesimal fineness expresses the purity of a precious metal as parts per thousand. For example, 18K gold has a fineness of 750, meaning 750 parts out of 1000 are pure gold.

Can gold be more than 24 karat?

No. 24 karat is the maximum on the karat scale and represents 99.9% purity. Values above 24K do not exist in standard gold grading.

How do I read a gold hallmark?

Common hallmarks include three-digit numbers like 750 (18K), 585 (14K), or 375 (9K). These numbers represent the millesimal fineness — the amount of pure gold per 1000 parts.

What is the difference between 10K and 14K gold?

10K gold is 41.7% pure gold, while 14K gold is 58.3% pure. 14K has a richer yellow color and higher value, while 10K is more durable and less expensive.

Karat to Gold Percentage Converter

Enter a karat value between 1 and 24 to instantly see the gold purity percentage and millesimal fineness.

Karat Converter

Karat Value (1 – 24)

Accepts decimal values (e.g. 9, 14, 18, 22, 24)

Standard Karat Reference Table

Karat	Purity %	Fineness	Hallmark / Notes

Summary

Gold purity is expressed in karats on a scale of 1 to 24, where 24K means pure gold. This converter calculates the exact percentage of gold and the millesimal fineness (parts per thousand) for any karat value. Use the reference table to identify common hallmarks used on jewelry and bullion worldwide.

How it works

Enter a karat value between 1 and 24 in the input field.
The tool divides the karat by 24 and multiplies by 100 to get the gold percentage.
Millesimal fineness is calculated by dividing the karat by 24 and multiplying by 1000.
The result is displayed immediately alongside common uses for that karat.
Scroll down to view the complete reference table for all standard karat marks.

Use cases

Verify the gold content of a piece of jewelry before purchase.
Convert between karat, percentage, and millesimal fineness for valuation.
Identify hallmarks stamped on rings, necklaces, and bangles.
Compare the purity of gold bars and coins from different mints.
Educate students or customers about gold grading standards.
Calculate the melt value of scrap gold based on purity.

Frequently Asked Questions

Last updated: 2026-05-28 · Reviewed by Nham Vu