Quebec GST + QST: rates, registration and Revenu Québec filing

Quebec's two-tax structure — separately administered

Quebec is the only Canadian province that maintains its own sales-tax administration. The federal 5% GST runs through the CRA exactly as it does in every other province. On top of it, the Quebec Sales Tax (QST) at 9.975% is administered by Revenu Québec separately. Businesses register with both agencies independently, file two separate returns each period, and reconcile two separate small-supplier thresholds. This is more administrative overhead than any other province, but Quebec gets to set its own QST rules (e.g. QST extends to financial services in ways the federal GST does not).

Critically, the QST is applied to the GST-inclusive price under the 'cascaded' computation rule. So on a $100 sale: GST = $5 (5% of $100), QST = $9.9750 (9.975% of $100 — the rule was changed in 2013 so QST now applies to the pre-GST price; the effective combined rate is 14.975%, not the slightly higher 15.025% that the old cascading rule produced). Always verify your POS / billing system uses the post-2013 calculation.

Two registrations, two thresholds, and the non-resident wrinkle

Federal GST registration is mandatory once worldwide taxable supplies exceed CAD 30,000 in trailing 4 quarters (the small-supplier threshold). QST registration follows the same threshold for resident vendors. Non-resident vendors who sell digital products or services to Quebec consumers face a lower 'specified registration' threshold (the QST equivalent of the federal Place-of-Supply non-resident regime) and may need to register for QST even when below the federal small-supplier threshold.

Input tax credits work in parallel: GST paid on business inputs flows back as Input Tax Credits (ITCs) on the federal GST return. QST paid on business inputs flows back as Input Tax Refunds (ITRs) on the Revenu Québec return. Most large-corporation rules also limit ITR claims on certain expenses (meals & entertainment 50% restriction, club dues, etc.) — verify Quebec-specific restrictions when claiming ITRs vs ITCs because they don't always match.

Filing cadence and Revenu Québec online services

GST filing frequency: annual under CAD 1.5M revenue, quarterly CAD 1.5M–6M, monthly above CAD 6M. Returns via GST/HST NETFILE to the CRA. QST filing frequency follows the same brackets but is filed via Revenu Québec online services (clicSÉQUR for business). Different registration numbers, different portals, different due dates in some scenarios (Revenu Québec usually accepts the same end-of-month-following deadline). Annual reconciliation alignment is the main administrative win — schedule both returns on the same monthly close.