How to Collect and Remit QST as a Small Business in Quebec — Montreal CPA Firm Near You

Collecting and remitting QST is one of the most important duties for any Quebec business. Whether you run a consulting service, retail shop, e-commerce store, beauty clinic, or construction company, QST applies to most of your sales. But new business owners often misunderstand how QST works, resulting in under-collection, over-collection, incorrect remittances, or late filings. Revenue Québec takes QST compliance very seriously because QST is a trust tax—money you hold on behalf of the province. This guide shows you exactly how to collect, track, and remit QST professionally, using the same structure Mackisen CPA Montreal implements for clients to avoid costly errors.

Why QST Collection Matters
When you collect QST, you are holding government money. If you calculate incorrectly or forget to remit the amounts, Revenue Québec can impose penalties, freeze refunds, and issue garnishments. QST errors accumulate fast because every transaction is affected. Proper collection protects your reputation, cash flow, and compliance history.

Legal and Regulatory Framework
QST is governed by the Tax Administration Act (Quebec) and is harmonized with GST rules under the Excise Tax Act. QST must be collected at 9.975% on the GST-inclusive amount. Hickman Motors (1997, SCC) reinforces the taxpayer’s burden of proof. Lac d’Amiante (2001, SCC) confirms Revenue Québec’s right to reassess when tax collection is inaccurate.

What Happens When You Don’t Collect QST Properly
Imagine a scenario where your business grows quickly. You are issuing invoices without QST because you assumed you hadn’t reached the $30,000 threshold or believed QST didn’t apply to your online sales. Two years later, Revenue Québec audits your IT returns and compares them to your bank deposits. They determine you should have been collecting QST for 24 months. Now you owe tens of thousands in QST you never collected from your customers. You must pay the full amount out of pocket—plus interest and penalties. This nightmare happens often and is completely avoidable.

Learning Section: When You Must Collect QST
You must collect QST once you exceed $30,000 in taxable worldwide revenues. This includes local clients, out-of-province clients (depending on service), online shoppers, and foreign customers using your services in Quebec. Voluntary registration is often recommended because it enables you to claim Input Tax Refunds (ITRs) and avoids the panic of forced retroactive registration.

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How to Collect QST Correctly
Step 1: Calculate GST at 5% of your subtotal.
Step 2: Add GST to the price.
Step 3: Calculate QST at 9.975% of this new total.
Step 4: Add both taxes separately to your invoice.
Step 5: Record the taxes separately in your accounting software.

How to Remit QST
Log into Mon Dossier
Select FPZ-500-V
Enter QST collected and ITRs
Submit return
Pay online
Keep confirmation receipts
All numbers must reconcile with your books and bank deposits.

Documentation Section: What You Must Keep
Invoices showing QST
POS reports
E-commerce order summaries
Bank statements
Merchant processor statements
Invoice templates
Reconciliation worksheets
Proof of payment for expenses claimed as ITRs
These must be kept for six years.

Common Mistakes
Charging QST incorrectly
Failing to charge QST after crossing $30,000
Not remitting QST collected
Incorrect calculations in software
Missing supplier tax numbers
Not reconciling taxes monthly

Winning With Revenue Québec and Canada
Mackisen configures your invoicing and POS systems, reconciles QST monthly, ensures accurate remittances, and prepares audit-ready documentation. We eliminate errors before they appear on your return.

Mackisen Service Hub
We manage QST collection, remittance, reconciliation, compliance reviews, and communication with Revenue Québec.

Why Mackisen
With over 35 years of CPA expertise, Mackisen CPA Montreal ensures your QST is collected, tracked, and remitted correctly protecting your business from penalties, interest, and heavy-handed enforcement.