This is a combination of:
Sale tax is applied on the purchase or lease price of goods and services aside from certain exceptions.
Taxes in Canada are destination-based, meaning the sales tax rate is based, or determined from, the destination location an item is shipped to. This complicates business for retailers who need to have the exact and up-to-date sales tax rate for every shipment they make.
To see a full breakout of Canada sales tax rates by province, city and postal code, subscribe to our .csv Canada Tax Table.