What Is Quebec QST and How Does It Work?

Why Quebec QST Matters for E-Commerce Sellers

Registering for GST/HST does not automatically register you for QST. This is the single most common mistake we see among sellers expanding into Quebec, and it means tax owed on Quebec sales goes uncollected until someone catches the gap.

Missing QST registration creates the same exposure as missing GST/HST registration: back taxes on sales already made, calculated after the fact, with no way to collect it from customers who already paid. The financial risk compounds because you are now dealing with two tax authorities instead of one.

Getting QST right also unlocks refunds. Registered businesses can claim a QST input tax refund, the QST equivalent of a federal input tax credit, on eligible Quebec business expenses. Sellers who track only GST/HST input tax credits and ignore QST leave this money unclaimed.

Step-by-Step Guide to Quebec QST Compliance

Step 1: Confirm You Have Crossed the Threshold

QST registration follows the same small supplier threshold logic as GST/HST: $30,000 CAD in worldwide taxable revenue within a calendar quarter or over four consecutive quarters. If you have already registered for GST/HST under this threshold, check whether you have separately registered for QST, since the two are not automatically linked.

Step 2: Register With Revenu Québec

QST registration happens through Revenu Québec’s online services, a completely separate system from the CRA’s Business Registration Online portal used for GST/HST. Non-resident businesses, including US-based sellers, can register as specified registrants under Quebec’s simplified QST system if they meet the criteria. If you have not yet registered for GST/HST either, our guide on how to register for GST/HST walks through that separate federal process first.

Step 3: Apply the Combined Rate Correctly

QST is calculated on the sale price alone, not on the sale price plus GST. Charge 5% GST and 9.975% QST separately, shown as two distinct line items rather than one blended percentage, since Revenu Québec expects to see both amounts reported independently.

Step 4: Configure Your Sales Channels for Quebec

In Shopify, add your QST number alongside your GST/HST number under Canadian tax settings so both taxes calculate correctly for Quebec addresses. Our Shopify GST/HST guide covers the general Canadian tax settings this builds on. On Amazon, confirm your Quebec tax settings are enabled separately, since some sellers only configure the federal GST/HST fields and miss the QST field entirely.

Step 5: File Your QST Return Separately

QST returns are filed through Revenu Québec, on a different schedule and portal than your GST/HST return through the CRA. Keep both filing calendars visible, since missing one while filing the other on time is a common and costly gap. Our guide on filing your GST/HST return in QuickBooks Online explains the federal side; QuickBooks Online can track QST separately in the same way, using its own tax agency setup for Revenu Québec.

Step 6: Claim Your QST Input Tax Refund

Just like GST/HST input tax credits, QST paid on eligible Quebec business expenses can be claimed back and subtracted from what you owe. Review our full guide to GST/HST input tax credits for the underlying logic, since QST input tax refunds follow the same eligibility principles under a separate name.

Practical Tips for Better Results

Treat QST as a completely separate compliance task, not a line item inside your GST/HST process. Different portal, different login, different filing deadline.

Common mistake: assuming a GST/HST number covers Quebec sales. It does not. QST registration is mandatory on its own once you cross the threshold and sell to Quebec customers.

Common mistake: calculating QST on the price after GST has been added. QST is calculated on the base sale price only, and combining the calculation incorrectly overcharges or undercharges customers.

Efficiency tip: set up your QuickBooks Online chart of accounts with separate liability accounts for GST and QST from the start. Untangling blended tax accounts after a year of sales is far more work than setting them up correctly the first time.

Conclusion

Quebec QST is not an extension of GST/HST. It is a separate tax, a separate registration, and a separate filing obligation through Revenu Québec. Sellers who treat it as its own compliance task, with its own account setup and filing calendar, avoid the gap that catches most first-time Quebec sellers.

Not sure if your Quebec sales already require QST registration? Book a free consultation and we will review your Quebec revenue and current registration status together.