The provincial mosaic
Canada doesn’t have a single national sales-tax rate. The federal GST is 5% everywhere. On top of that, five provinces (ON, NB, NS, PE, NL) have replaced their separate provincial tax with a combined HST rate administered by the CRA. BC, Saskatchewan and Manitoba run separate provincial sales taxes (PST/RST). Quebec runs QST through Revenu Québec. Alberta and the three territories charge GST only.
Add-tax vs extract-pre-tax
Use add tax when you have a sticker price or quote and want to know what you’ll actually pay. Use extract pre-tax when you have a receipt total and want to back out the GST/HST for an expense report — handy for self-employed Canadians claiming Input Tax Credits on their GST/HST return.
What\u2019s zero-rated and what\u2019s exempt
Basic groceries, prescription drugs, most medical devices, exports, and financial services are zero-rated for GST/HST (the GST charged is 0%, and input tax credits are recoverable). Educational tutoring, residential long-term rent, and some health services are exempt (no GST/HST charged, but input tax credits are not recoverable). Provincial taxes have similar but not identical zero-rated lists — Ontario zero-rates books for HST, BC zero-rates them for GST, etc.