How to Register for GST and QST in Quebec: Step-by-Step for New Businesses — Montreal CPA Firm Near You

Registering for GST and QST is the first legal and financial milestone for any new business in Quebec. Whether you are launching a consulting company, e-commerce store, construction firm, beauty clinic, or professional practice, registration determines how you charge tax, recover tax, file returns, and interact with Revenue Québec and the CRA. Yet, thousands of entrepreneurs register late, register incorrectly, or assume registration is optional — until they receive a letter from Revenue Québec demanding retroactive tax, penalties, and daily-compounding interest. This guide teaches you everything you need to know about registering correctly the first time, following the exact checklist we use at Mackisen CPA Montreal to onboard new businesses safely and professionally.

Why GST/QST Registration Matters
GST (5%) and QST (9.975%) are trust taxes. When you collect them, you are holding tax in trust for the government. Registering correctly protects you from retroactive assessments, denied input credits, refund freezes, and audit exposure. Most importantly, proper registration lets you claim back the GST/QST paid on business expenses — which can be thousands of dollars for a startup. Without registration, you lose that refund.

Legal and Regulatory Framework
Registration rules fall under the Excise Tax Act and Quebec’s Tax Administration Act. These laws require businesses to register when their worldwide taxable supplies exceed $30,000 in the last four consecutive calendar quarters or when they exceed $30,000 in a single quarter. Certain industries such as taxi/Uber drivers, alcohol and tobacco retailers, short-term lodging operators, and non-resident digital businesses must register even below the threshold.

When You MUST Register for GST and QST
You are legally required to register when your total worldwide taxable revenues exceed $30,000. This includes revenue from Canadian clients, foreign clients, online sales, digital services, Stripe/PayPal payments, and side businesses under your name or control. Many entrepreneurs mistakenly think the $30,000 only applies to Quebec sales, but Revenue Québec counts global taxable revenue. If you reach $30,000 on a single invoice, you must register immediately — that very day — and tax applies starting from that sale onward.

Why You Should Register Even if You’re Under $30,000
Voluntary registration is often financially smarter. You can recover all GST/QST paid on startup costs such as rent, software, legal fees, marketing, equipment, and inventory. For a business investing $10,000 to start up, this can mean $1,500+ in refunds. Corporate clients expect invoices with GST/QST numbers, and many will not pay invoices without them. Voluntary registration also protects you from panic if you unexpectedly cross the threshold.

Step-by-Step: How to Register for GST (CRA)
Step 1: Log into CRA My Business Account or create one.
Step 2: Select “Business Registration Online,” then choose “GST/HST (RT).”
Step 3: Enter your legal business name, business number, address, activity type, and fiscal year.
Step 4: Enter the effective date of commercial activities — when you first entered business with a reasonable expectation of profit.
Step 5: Confirm and obtain your RT0001 account number instantly.
Keep your confirmation and setup documents for compliance records.

Step-by-Step: How to Register for QST (Revenue Québec)
Step 1: Log into Mon Dossier pour les enterprises.
Step 2: Select “Register a QST Account.”
Step 3: Enter business identification, description of activities, expected revenues, and effective date.
Step 4: Receive your TQ number and activate your online services.
Step 5: Verify your mailing address and banking for direct deposit of refunds.
Revenue Québec will use this account to communicate notices, penalties, and refund updates — so keep login credentials secured.

What Happens If You Register Late
Imagine receiving a letter titled “Avis d’Enregistrement Obligatoire.” Revenue Québec informs you that based on your bank deposits, e-commerce activity, online sales, or income tax filings, they believe you crossed the $30,000 threshold months ago. They demand retroactive registration. Now every invoice you issued without tax must be recalculated with GST/QST — but you cannot go back to clients and collect it. You owe thousands in tax you never collected. Interest begins accruing daily. Your refund claims are frozen. Your file is flagged for a review. This scenario is extremely common and entirely preventable with early registration.

Learning Section: How to Know Your Registration Date
Your “effective date of registration” is not the date you receive your tax numbers. It is the date your commercial activity began or the date you exceeded the threshold. Understanding this distinction ensures proper filing periods, correct refund claims, and avoids re-assessments.

SEO Learning: Primary and Secondary Keywords
Primary keywords: GST registration Quebec, QST registration Quebec, how to register GST QST, Montreal CPA GST/QST. Secondary keywords: small supplier rules Quebec, tax registration thresholds, startup GST refund, Revenue Québec GST QST compliance.

Documentation Section: What You Must Keep
GST/QST confirmation letters
Business number (BN) assignment
RT and TQ account activation documents
Incorporation documents or NEQ

Chart of accounts with GST/QST ledgers
Invoices showing tax
Bank statements showing tax-related payments
CRA and RQ portal screenshots
These must be retained for at least six years under the Tax Administration Act.

Winning With Revenue Québec and Canada: How Mackisen Ensures Success
Registration alone is not enough. Mackisen ensures your registration date, accounting system, invoice templates, POS systems, and e-commerce platforms are configured correctly. We create a compliance file so that if Revenue Québec reviews your first refund or your first return, everything is supported, accurate, and defensible. We set up a GST/QST holding account, so tax collected is never mixed with operating funds. We protect you from the mistakes most new businesses make.

Mackisen Service Hub
Our Montreal team of CPAs, auditors, and tax lawyers offers full registration, system setup, documentation review, and compliance management. We work with startups, freelancers, retailers, contractors, clinics, e-commerce sellers, and corporations. We handle correspondence with CRA and RQ, troubleshoot portal issues, prepare first-year returns, and ensure audit-proof accuracy.

Why Mackisen
With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps businesses stay compliant while maximizing tax refunds and minimizing audit risk. Whether you are filing your first GST/QST return or optimizing multi-year refunds, our expert team ensures precision, transparency, and protection from audit exposure.