A karat (K, also written carat or ct) measures gold purity in 24ths: 24 karat is pure gold, 18 karat is 18 parts gold in 24 (75%), and 10 karat is about 41.6%. It is not the same as the carat used to weigh diamonds.
Karat to fineness conversion
To convert a karat number to purity, divide it by 24. Canadian rules accept both spellings on jewellery: "K", "Kt" or "Karat", and "C" or "Ct", or a decimal such as .583. Bullion is normally stamped in fineness instead.
| Karat | Gold content | Decimal mark | Where you see it |
|---|---|---|---|
| 24K | 99.9% and above | 999 / 999.9 | Bullion coins and bars, such as the Gold Maple Leaf |
| 22K | 91.67% | .916 | Krugerrand, American Gold Eagle |
| 18K | 75% | .750 | Fine jewellery |
| 14K | 58.3% | .583 | Jewellery |
| 10K | 41.6% | .416 | Jewellery |
| 9K | 37.5% | .375 | The lowest gold quality that can carry a quality mark in Canada |
Worked example: a 20 g 18K chain holds 20 x 0.75 = 15 g of gold. A 20 g 10K chain holds about 8.3 g, roughly a quarter of a troy ounce. The rest is silver, copper, zinc or other metals, which shape the colour (yellow, rose or white gold) and the hardness.
Jewellery is not bullion
Karat gold jewellery sells for well above its metal value because you pay for design, labour and retail margin. When you sell it to a gold buyer, you are paid for the fine gold only, minus a margin. The CRA also names carat gold jewellery as an example of metal that is not "precious metal" for GST/HST, so new jewellery is taxable. Gold of at least 99.5% in bar or government-issued coin form is generally exempt; see GST/HST on gold.
22 karat sits in the middle. The Krugerrand is a bullion coin in every practical sense, priced close to spot, yet at 91.67% it misses the 99.5% line and is generally taxable. Compare it with a 24 karat 1 oz Gold Maple Leaf before you assume the cheaper headline is the cheaper coin. If you buy Krugerrands second-hand, our guide to spotting a fake Krugerrand lists the specifications to check.
Scrap value of karat gold
To estimate what an old 10K or 18K piece is worth as metal, multiply its weight in grams by its purity and by the gold price per gram in CAD. Buyers then deduct their margin, which is a form of bid-ask spread. Weigh items without stones, since diamonds and gems add weight but no gold. The diamond carat is a unit of weight (0.2 g), not purity.
Related terms
Fineness Troy Ounce GST/HST on Gold and Silver in Canada Bid-Ask Spread
FAQ
How much gold is in 10K gold?
10 karat gold is 10 parts in 24, or about 41.6% pure gold, marked .416 in Canada, with the rest made up of other metals.
Is 24 karat gold the same as 9999?
Both mean pure gold; 24 karat covers 99.9% and above, while 9999 specifies 99.99%, the standard for the Gold Maple Leaf.
Is 22 karat gold a good investment in Canada?
22 karat coins contain full ounces of gold but are below the 99.5% GST/HST threshold, so they are generally taxable; compare their final price with 24 karat coins first.