How to Manage GST/QST When Your Business Operates in Quebec and Ontario — Montreal CPA

When a business operates in both Quebec and Ontario, sales tax compliance becomes significantly more complex. Quebec uses GST + QST, while Ontario uses HST. Rules differ based on whether goods or services are delivered, where customers are located, and how digital products are consumed. A single mistake — such as charging QST to an Ontario customer — can trigger disputes, reassessments, and audit risk. This guide explains how to properly apply GST/QST/HST when operating in both provinces using Mackisen’s interprovincial compliance model.

Why Proper Multi-Province Tax Management Matters
Incorrectly charging QST to an Ontario customer, or failing to charge HST when required, leads to amendment filings, angry clients, and RQ/CRA corrections. E-commerce sales, consulting services, digital products, and B2B transactions all have unique rules.

Legal and Regulatory Framework
GST/HST rules fall under the Excise Tax Act. QST rules fall under the Tax Administration Act. Place-of-supply rules determine which tax applies. Hickman Motors (1997) affirms the taxpayer’s duty to apply correct tax. CRA’s GST/HST Technical Bulletins define Ontario-specific rules.

The Two-Province Audit Nightmare
Imagine your business sells services in Quebec and Ontario. You’ve been charging QST to Ontario clients for two years. During a CRA review, they discover the mistake and require you to refund clients, correct two years of returns, and remit HST instead. Meanwhile, Revenu Québec demands adjustments for all misapplied QST. Refunds freeze. Your business faces a two-agency correction nightmare.

Learning Section: Key Differences Between Quebec and Ontario
Quebec → GST + QST
Ontario → Single HST tax
Goods taxed based on delivery address
Services taxed based on customer location
Digital products taxed based on user location
Consulting services often follow client location rules

SEO Learning: Primary and Secondary Keywords
Primary: Quebec Ontario tax rules, GST QST HST guide, multi-province sales tax Canada.
Secondary: Ontario HST vs Quebec QST, cross-province tax compliance, Montreal CPA multi-province tax.

How to Manage GST/QST/HST Properly
For Quebec customers: charge GST + QST
For Ontario customers buying goods: charge HST
For Ontario customers buying services: usually HST
For digital services: based on user location
For exports outside Canada: 0%
Track sales by province in accounting system
Reconcile merchant reports by location

Documentation Section
Invoices showing correct tax
Shipping confirmations
Client address verification
Platform reports
Reconciliation worksheets
Correspondence regarding tax agreements
Keep these for six years.

Common Mistakes
Charging QST to Ontario clients
Charging HST to Quebec clients
Not separating sales by province
Incorrect digital taxation
Failing to reconcile Stripe/Shopify data by location

Winning With Revenue Québec and Canada
Mackisen configures your accounting and e-commerce systems to correctly apply GST/QST/HST based on province. We reconcile multi-province data monthly and prepare audit-proof documentation.

Mackisen Service Hub
We manage multi-province filings, interprovincial tax mapping, invoicing setup, reconciliation, and audit defense.

Why Mackisen
With more than 35 years of CPA expertise, Mackisen ensures your cross-province operations remain fully compliant and protected from reassessments.