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Quebec QST Explained: How to Calculate and Charge It

QST has two quirks that trip people up. Here’s how to get it right.

The short answer

QST is 9.975% — calculated on the base price, not on GST

The Quebec Sales Tax (QST) rate is 9.975%, and it is calculated on your selling price before GST — not on the GST-inclusive amount. On a $100 sale: GST = $5.00, QST = $9.975. Both are calculated on the original $100, shown as two separate lines on the invoice. Total: $114.975.

The second thing to know immediately: QST is administered by Revenu Québec, not the CRA. If you sell to Quebec customers and need to collect QST, you register with Revenu Québec directly — your CRA GST number does not cover Quebec. Quebec businesses also file their GST returns with Revenu Québec (not the CRA), under an agreement between the federal and provincial governments.

How it works

QST calculation, registration, and filing

The calculation, step by step

  1. Start with your base selling price (before any tax).
  2. Calculate GST: base price × 5%.
  3. Calculate QST: base price × 9.975%.
  4. Show GST and QST as two separate line items on the invoice.
  5. Total = base price + GST + QST.

Source: Revenu Québec — “the Québec sales tax (QST), which is calculated at a rate of 9.975% on the selling price excluding the GST”

Invoice examples at three price points

$100 sale to a Quebec customer

Subtotal$100.00
GST (5%)$5.00
QST (9.975%)$9.975
Total$114.975

Both GST and QST calculated on the base price. Two separate line items required.

$500 service invoice to a Quebec client

Subtotal$500.00
GST (5%)$25.00
QST (9.975%)$49.875
Total$574.875

Both GST and QST calculated on the base price. Two separate line items required.

$2,500 project invoice to a Quebec client

Subtotal$2,500.00
GST (5%)$125.00
QST (9.975%)$249.375
Total$2,874.375

Both GST and QST calculated on the base price. Two separate line items required.

Free tool

Calculate your exact rate

Use our free Canadian sales tax calculator to get the answer for your specific situation — seller province, buyer province, and product type — with government sources cited.

Use the free calculator

Who needs to register for QST

Quebec-based businesses

If your business is physically in Quebec and your total worldwide taxable supplies exceed $30,000 over four consecutive calendar quarters, you must register for both GST and QST with Revenu Québec. Revenu Québec administers both taxes for Quebec businesses under a federal-provincial agreement.

Out-of-province sellers with Quebec customers

If you are based outside Quebec but sell taxable goods or services to Quebec customers, and your revenues exceed $30,000, you need to register for QST with Revenu Québec separately. Your CRA GST registration covers the federal portion everywhere — but it does not create a QST obligation.

Mandatory registration regardless of revenue

Some businesses must register for QST regardless of revenue: tobacco retailers, fuel retailers, alcohol retailers, and those selling or leasing new tires or road vehicles for 12+ months. If your business falls into one of these categories, the $30,000 threshold does not apply.

Filing: Revenu Québec, not the CRA

If your business is in Quebec: you file both your GST/HST return and your QST return with Revenu Québec. You never deal with the CRA directly for GST/HST — Revenu Québec handles everything and passes the federal portion to Ottawa.

If your business is outside Quebec but registered for QST: you file your GST return with the CRA as normal and your QST return separately with Revenu Québec. Two separate filings, two separate remittances.

As of January 1, 2024, all GST and QST registrants (except charities) must file returns electronically.

What’s the effective combined rate in Quebec?

GST (5%) + QST (9.975%) = 14.975% total tax on a typical taxable sale in Quebec. This is slightly lower than Ontario’s 13% HST on paper but higher in practice because Quebec’s rate is applied to the same base (pre-tax price), making the effective total 14.975%. For budgeting purposes, round to 15%.

What most people get wrong

Common QST mistakes

Calculating QST on the GST-inclusive price

The most common calculation error. QST is 9.975% of the base price before GST — not of (base price + GST). On a $1,000 invoice: correct QST = $99.75. Wrong QST (on $1,050 including GST) = $104.74. The difference is small per invoice but compounds across many Quebec clients. Revenu Québec's own documentation explicitly states: "calculated at a rate of 9.975% on the selling price excluding the GST."

Thinking your CRA GST number covers Quebec

It doesn't. GST and QST are two separate registrations. You can be fully compliant with the CRA for GST/HST across all other provinces and be completely unregistered for QST in Quebec. If you have Quebec customers and your revenues exceed the threshold, you need to go to revenuquebec.ca and register separately.

Filing QST returns with the CRA

Out-of-province businesses sometimes send QST remittances to the CRA by mistake. QST goes to Revenu Québec — always. If you're based in Quebec, both GST and QST go to Revenu Québec. If you're based elsewhere, GST goes to CRA and QST goes to Revenu Québec.

Showing QST as a single combined line item on invoices

Quebec law requires GST and QST to appear as separate, clearly identified line items on invoices issued to Quebec customers. A single "tax" line lumping both together does not meet Revenu Québec's requirements. This matters especially if your Quebec customer is a registered business claiming input tax credits — they need the split to file their own returns correctly.

Assuming the small supplier exemption works the same way as GST

The QST registration threshold mirrors the federal $30,000 threshold in principle, but there are mandatory registration categories that override it (tobacco, fuel, tires, etc.). More importantly, for out-of-province sellers who are already registered for GST, the question of whether the QST threshold applies to your world-wide revenue or just Quebec revenue is worth confirming with a tax professional if you're close to the line.

Summary

Key takeaways

  • QST rate is 9.975%, calculated on the base price before GST — not on the GST-inclusive amount.

  • GST (5%) and QST (9.975%) are calculated on the same base price independently. Combined effective rate: 14.975%.

  • Both taxes must appear as separate line items on invoices issued to Quebec customers.

  • QST is administered by Revenu Québec — a separate registration from your CRA GST/HST number.

  • Quebec-based businesses file both GST and QST returns with Revenu Québec (not the CRA).

  • Out-of-province businesses registered for QST file GST with CRA and QST with Revenu Québec separately.

  • The registration threshold mirrors the federal $30,000 threshold, but some business categories must register regardless of revenue.

  • Electronic filing is mandatory for all GST and QST registrants (except charities) as of January 1, 2024.

Free tool

Calculate your exact rate

Use our free Canadian sales tax calculator to get the answer for your specific situation — seller province, buyer province, and product type — with government sources cited.

Use the free calculator

Government sources

Sources

Every rule and rate in this article comes from official Revenu Québec and CRA publications. QST rules have changed over time — verify current rates and requirements directly before invoicing or filing.

Keep reading

Related guides

Selling From Quebec to Other Provinces: Which Tax Applies?

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GST vs HST: What's the Difference for Canadian Businesses?

Full rates table for all 13 provinces, invoice examples, and why the customer's province — not yours — determines the rate.

Freelancer Selling Services Across Provinces: Which Tax Rate to Charge?

The CRA place-of-supply rule most freelancers don't know — and how it interacts with QST when you have Quebec clients.

Disclaimer

TaxMapCA provides tax information, not tax advice. This article is for general informational purposes only and does not constitute legal or accounting advice. QST rules and rates may change — always verify current requirements against the Revenu Québec sources linked above before invoicing or filing. TaxMapCA is not affiliated with or endorsed by Revenu Québec, the Canada Revenue Agency, or any government agency. For complex situations, consult a qualified CPA or tax professional.