Troy Ounce

Canada measures almost everything in metric, but gold and silver are still priced per troy ounce. This entry covers what that means when you compare prices here: fine weight, gross weight and the cost per ounce in CAD.

Gross weight and fine weight

What you pay for is the fine weight: the amount of pure metal inside. The gross weight includes any alloy. Two coins that both contain one troy ounce of gold can therefore weigh different amounts on your scale:

• The Royal Canadian Mint's 1 oz Gold Maple Leaf is struck in 99.99% gold and weighs 31.11 g, so gross and fine weight are almost identical.
• A South African Krugerrand is 22 karat (91.67% gold). To hold one troy ounce of fine gold it weighs about 33.93 g, with copper making up the rest.

Worked example: 33.93 g x 0.9167 = 31.10 g of fine gold, which is one troy ounce. The extra 2.8 g of copper adds hardness, not value. Read more about purity in our entry on fineness and how alloys are expressed in karats.

Silver works the same way. The 1 oz Silver Maple Leaf contains one troy ounce (31.11 g) of 99.99% silver.

Converting troy ounces to CAD prices

International spot prices are quoted in US dollars per troy ounce. Canadian dealers convert that figure into CAD at the current exchange rate, so the Canadian price can move even on a day when the US dollar gold price is flat. If you think in grams, divide the price per troy ounce by 31.1035, or use our gold price per gram in CAD. For larger holdings, the gold price per kilogram is handy, and silver buyers can follow the silver price per kilogram for 1 kg bars.

Fractional coins are labelled in parts of a troy ounce: 1/2, 1/4, 1/10 and 1/20 oz. A 1/10 oz coin holds 3.11 g of gold, but its price per gram is usually higher than a 1 oz coin because minting costs are spread over less metal. That difference is the premium over spot, which we rank for every product in our list of the cheapest gold coins in Canada.