How to File GST/QST Returns for Multiple Provinces (Inter-Provincial Sales) — Montreal CPA

Businesses expanding outside Quebec quickly learn that GST, QST, and HST rules across provinces vary significantly. Charging the wrong tax to out-of-province customers is one of the most common and costly mistakes made by Quebec businesses. If you sell goods or services to Ontario, British Columbia, Alberta, Manitoba, Saskatchewan, or the Atlantic provinces, you must apply the correct tax using place-of-supply rules. This guide explains how to properly file GST/QST returns for multi-province sales using Mackisen’s expert interprovincial tax strategy.

Why Inter-Provincial Filing Matters
Each province has different sales tax rules:
Quebec → GST + QST
Ontario → HST
Maritimes → HST
Western Provinces → GST only
Saskatchewan/Manitoba → GST + PST
Charging the wrong tax creates refund issues, customer complaints, and audit exposure. Revenue Québec and CRA verify place-of-supply rules during review.

Legal and Regulatory Framework
Interprovincial sales tax rules fall under the Excise Tax Act and Tax Administration Act. Place-of-supply rules determine which tax to charge. Hickman Motors (1997) confirms the taxpayer’s duty to apply tax correctly. Canderel (1998) requires filings that reflect commercial reality. CRA’s GST/HST Technical Information series outlines rules for interprovincial taxes.

What Happens When You Charge the Wrong Tax
Imagine selling software services to a client in Ontario but charging GST + QST instead of HST. The client refuses to pay the invoice. You must issue credit notes, adjust prior returns, and correct CRA filings. Even worse, CRA may audit your multi-province transactions and require corrections for years of misapplied tax. Many businesses discover massive errors only after auditors contact them.

Learning Section: How Place-of-Supply Works
For goods: tax depends on where the product is delivered
For services: tax depends on customer location
For digital services: tax depends on user location
For interprovincial B2B sales: GST/HST applies based on customer address
For exports: usually zero-rated
You must determine the correct tax BEFORE issuing invoices.

SEO Learning: Primary and Secondary Keywords
Primary: interprovincial GST rules Canada, QST out-of-province sales, HST vs QST guide.
Secondary: place of supply Quebec, multi-province tax filing, GST for Ontario clients.

How to File Multi-Province GST/QST Returns Correctly
Step 1: Charge GST, QST, or HST based on customer province
Step 2: Track sales by province in your accounting system
Step 3: Reconcile merchant processor payouts
Step 4: Report GST collected to CRA
Step 5: Report QST collected to RQ
Step 6: Adjust for PST in BC, SK, MB if applicable
Step 7: Maintain full documentation for each interprovincial sale
Step 8: File returns according to each agency’s rules

Documentation Section
Customer location evidence
Sales invoices showing correct tax
Shipping confirmations
Service contracts
Merchant processor reports
Accounting system tax breakdowns
CRA/RQ filing confirmations
You must keep all records for six years.

Common Mistakes
Charging QST to Ontario clients
Charging GST only when HST applies
Failing to collect PST in provinces requiring it
Incorrect digital service tax
Using billing address instead of delivery address
Not tracking interprovincial sales separately

Winning With Revenue Québec and Canada
Mackisen configures your accounting system for multi-province sales, verifies each province’s tax rules, prepares GST/HST/QST filings, reconciles interprovincial deposits, and defends your file during CRA/RQ reviews.

Mackisen Service Hub
We provide interprovincial tax compliance, GST/HST/QST filing, tax-rule setup in software, reconciliation, refund management, and audit defense.

Why Mackisen
With over 35 years of CPA experience, Mackisen ensures your interprovincial tax filings are accurate, compliant, and protected from reassessments, no matter where your customers are in Canada.