How much gold is in 24K, 18K and 14K?
Karat expresses gold as parts out of 24 by mass. In a 10-gram metal piece, 18K means 7.50 grams of gold; 14K means about 5.83 grams using the nominal karat fraction.
Purity and total weight answer different questions
A karat mark describes the fraction of a metal object's mass that is gold. Dividing by 24 gives its nominal gold fraction. For example, a 10-gram 18K piece contains 10 × 18 ÷ 24 = 7.50 grams of gold. The remaining 2.50 grams consists of other alloy metals.
The rows hold total metal mass constant so the comparison isolates purity. They do not compare jewellery prices: craftsmanship, stones, condition and selling costs are outside the calculation. “Karat” here describes gold purity; the similarly spelled carat used for gemstones is a unit of mass.
| Nominal purity | Gold by mass | Fine gold | Other metals |
|---|---|---|---|
| 24K | 100.00% | 10.00 g | 0.00 g |
| 22K | 91.67% | 9.17 g | 0.83 g |
| 18K | 75.00% | 7.50 g | 2.50 g |
| 14K | 58.33% | 5.83 g | 4.17 g |
| 10K | 41.67% | 4.17 g | 5.83 g |
| 9K | 37.50% | 3.75 g | 6.25 g |
How a 22K coin can contain a full ounce of gold
The U.S. Mint's one-ounce American Gold Eagle contains one fine troy ounce of gold even though it is a 22K alloy. Its published total weight is 1.0909 troy ounces: the extra mass accommodates the alloy metals. A lower purity therefore does not automatically mean less gold when the total weights differ.
For a particular item, use its actual stated fineness. A mark of 750 denotes 750 parts gold per thousand; 999.9 denotes 99.99%. The nominal 24K endpoint in this diagram is the mathematical pure-gold limit, not a claim that every product sold as 24K is literally 100.000% gold. Small differences such as 14/24 versus a stated 585 fineness should be calculated from the product's stated figure.
Formula: fine-gold mass = metal-only mass × karat ÷ 24, or metal-only mass × fineness ÷ 1,000. A surface plating cannot be evaluated as though the entire object's mass had that purity.
Sources and calculations
Source checks: 22 October 2026. The graphic is drawn from the accompanying values and formulas. Source data retain their own terms; a downloadable image does not change those terms.
- The Royal Mint, Metal Fineness Explained
What is a carat? Gold purity and fineness: a 24-part ratio
- U.S. Mint, Bullion Coin Programs
American Eagle Gold Bullion Coins specifications: 91.67% gold; one-ounce size weighs 1.0909 troy oz / 33.931 g
Gold Per Capita. “How much gold is in 24K, 18K and 14K?.” 2026-10-22. https://goldpercapita.com/infographics/gold-purity-karats