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How Discounts and Sales Tax Work in Canada

In Canada, sales tax is calculated on the discounted price, not the original retail price. This means a 25% discount on a $200 item in Ontario (13% HST) saves you not just the $50 discount but also $6.50 in tax you would have paid on that amount. Understanding this compounding effect reveals the true value of a sale — the effective savings are always slightly larger than the posted discount percentage when tax is factored in.

Canada’s sales tax structure varies significantly by province. Alberta has no provincial sales tax, charging only the 5% federal GST, making it the lowest-tax shopping jurisdiction in the country. The Atlantic provinces (New Brunswick, Newfoundland, Nova Scotia, and PEI) apply a 15% HST — the highest combined rate. Certain goods are exempt from sales tax nationwide, including basic groceries, prescription medications, and most medical devices.

Sales Tax Rates by Province (2026)

When evaluating sale prices, be wary of inflated “original” prices. The Competition Act requires that any advertised regular price must have been the actual selling price for a substantial period. Retailers who inflate the reference price to make a discount appear larger are engaging in deceptive marketing, which the Competition Bureau actively investigates. Comparing prices across multiple retailers and using price-tracking tools will confirm whether a sale genuinely represents good value.