QST (Quebec Sales Tax)
The QST is Quebec's provincial sales tax at 9.975%, administered by Revenu Québec (not the CRA). Combined with the 5% federal GST, the total sales tax rate in Quebec is approximately 14.975%. QST generally mirrors the GST in terms of what is taxable, exempt, and zero-rated.
Businesses operating in Quebec must register for both GST (with the CRA) and QST (with Revenu Québec), and file separate returns for each. Revenu Québec administers the GST on its behalf in Quebec, so Quebec businesses actually file both GST and QST returns through Revenu Québec.
The QST is calculated on the sale price before GST — it is not a tax-on-tax. This means the effective combined rate is exactly 14.975%, not higher. Quebec small businesses with revenues under $30,000 are exempt from QST registration, mirroring the GST small supplier threshold.
How it works
The QST is administered by Revenu Quebec rather than the CRA, and it generally mirrors the GST when it comes to what's taxable, exempt, or zero-rated, even though it's calculated and remitted through a separate system. Its rate is 9.975%, which is layered on top of the 5% federal GST for a combined effective rate.
Unlike a tax charged on top of another tax, the QST is calculated on the sale price before GST is added, not on the GST-inclusive total, so the combined rate works out to exactly 14.975% rather than compounding to something higher. This distinction matters because a true tax-on-tax calculation would produce a slightly higher effective rate.
Because Revenu Quebec also administers the GST within Quebec on the CRA's behalf, businesses operating there register for both GST and QST but file both returns through Revenu Quebec's own portal, rather than dealing with the CRA directly for the federal component. Quebec businesses under the $30,000 small-supplier threshold are exempt from QST registration, the same threshold that applies for GST.
Example: GST and QST on a $1,000 purchase in Quebec
On a $1,000 purchase, GST at 5% adds $50, and QST at 9.975% adds $99.75 - both calculated on the original $1,000 price, not on top of each other. Total tax comes to $149.75, for a final price of $1,149.75.
Dividing the total tax by the original price confirms the combined effective rate: $149.75 divided by $1,000 is 14.975%, exactly matching the sum of the 5% GST and 9.975% QST rates, with no compounding.
Frequently asked questions
Is QST charged on top of the GST amount, or on the original price?
It's calculated on the original pre-GST price, not the GST-inclusive total, which is why the combined GST and QST rate works out to exactly 14.975% instead of compounding higher.
Do Quebec businesses deal with the CRA for GST?
Not directly - Revenu Quebec administers the GST within Quebec on the CRA's behalf, so Quebec businesses file both their GST and QST returns through Revenu Quebec's own portal.
Is there a small-business exemption from QST registration?
Yes, businesses with revenue under $30,000 are exempt from QST registration, the same small-supplier threshold that applies for GST registration.
Related Terms
GST (Goods and Services Tax)
The GST is a 5% federal value-added tax applied to most goods and services sold in Canada.
HST (Harmonized Sales Tax)
HST combines the 5% federal GST with a provincial portion into a single harmonized tax, simplifying compliance for businesses operating in multiple provinces.
PST (Provincial Sales Tax)
PST is a provincial sales tax levied separately from the federal GST.
Revenu Québec
Revenu Québec is the provincial government agency that administers Quebec's tax laws, including the provincial income tax return (TP-1), Quebec Sales Tax (QST), and the Quebec Pension Plan (QPP).