Susan B. Anthony dollar in the context of United States dollar coin

The loonie (French: huard), formally the Canadian one-dollar coin, is a gold-coloured Canadian coin that was introduced in 1987 and is produced by the Royal Canadian Mint at its facility in Winnipeg. The most prevalent versions of the coin show a common loon, a bird found throughout Canada, on the reverse and Queen Elizabeth II, the nation's head of state at the time of the coin's issue, on the obverse. Various commemorative and specimen-set editions of the coin with special designs replacing the loon on the reverse have been minted over the years. Beginning in December 2023, a new version featuring King Charles III entered circulation.

The coin's outline is an 11-sided Reuleaux polygon. Its diameter of 26.5 mm (1.04 in) and its 11-sidedness match that of the already-circulating Susan B. Anthony dollar in the United States, and its thickness of 1.95 mm (0.077 in) is a close match to the latter's 2.0 mm (0.079 in). Its gold colour differs from the silver-coloured Anthony dollar; however, the succeeding Sacagawea and presidential dollars match the loonie's overall hue. Other coins using a non-circular curve of constant width include the 7-sided British twenty pence and fifty pence coins (the latter of which has similar size and value to the loonie but is silver in colour).