How to File Your GST/QST Return Online: A Step-by-Step Guide

Introduction

Filing your GST/QST return online is one of the most important obligations for any Quebec business. Whether you’re a self-employed professional, incorporated company, or small retailer, staying compliant with Revenu Québec and the Canada Revenue Agency (CRA) ensures you avoid penalties, maintain cash flow, and protect your business’s reputation.

This complete step-by-step guide from Mackisen CPA Montreal explains how to file your GST/QST return online through Mon dossier pour les entreprises, what documents you need, and how to avoid the most common filing mistakes that trigger audits or penalties.

Legal and Regulatory Framework

GST and QST are mandatory value-added taxes:

• GST (Goods and Services Tax) – 5% federal, governed by the Excise Tax Act (R.S.C. 1985, c. E-15).

• QST (Quebec Sales Tax) – 9.975% provincial, governed by the Quebec Sales Tax Act (R.S.Q., c. T-0.1).

All businesses whose worldwide taxable revenues exceed $30,000 in any 12-month period must register, collect, and remit these taxes. Returns must be filed even if there were no sales (nil return).

Filing Frequency

• Monthly – for high-volume taxpayers.

• Quarterly – for most small- to medium-sized businesses.

• Annual – for small suppliers and professionals with lower sales.

Filing deadlines:

• Monthly and quarterly – due one month after the end of the period.

• Annual – due three months after fiscal year-end.

Learning Insight

Filing on time—even with a balance owing—shows good faith. Late filing without communication can trigger interest, penalties, or automatic reassessment.

Step-by-Step: How to File GST/QST Online

Step 1 — Log in to Mon dossier pour les entreprises

Go to → Mon dossier pour les entreprises.
Sign in with your Revenu Québec access code or clicSÉQUR credentials.

Step 2 — Select Your Tax Accounts

Under “Consumption Taxes,” choose:

• TPS/TVH for GST/HST, and

• TVQ for QST.

Click “File a return.”

Step 3 — Confirm the Period

Ensure the return period displayed matches your accounting records. If the period shown is incorrect or missing, contact Revenu Québec before filing.

Step 4 — Enter Sales and Tax Information

You’ll be prompted for:

• Total taxable sales and revenues for the period.

• GST and QST collected.

• Input Tax Credits (ITCs) and Input Tax Refunds (ITRs) on eligible business expenses.

• Net tax owing or refund claimed.

If there were no sales, file a nil return—this still fulfills your obligation.

Step 5 — Review and Submit

Double-check your entries against your accounting software or summary spreadsheet. Submit electronically and download the confirmation receipt or PDF copy for your records.

Step 6 — Make Payment

You can pay by:

• Online banking (add Revenu Québec – TVQ and Revenu Québec – TPS as payees).

• Pre-authorized debit through Mon dossier.

• CRA “My Payment” if you also remit GST federally.

Record payment confirmation in your books immediately.

Learning Insight

Your filing history builds your compliance score. Consistent accuracy reduces audit risk and helps maintain trust with lenders and suppliers.

Frequent Errors That Trigger Penalties

• Missing the $30,000 registration threshold and filing late.

• Failing to file nil returns.

• Misreporting QST or GST on exempt items.

• Forgetting to include instalments already paid.

• Claiming ITCs/ITRs without proper invoices.

Learning Insight

Revenu Québec’s AI-based systems cross-check your GST/QST filings against income tax and payroll data. Even small mismatches can trigger an audit. Keep your bookkeeping synchronized across all accounts.

Real Quebec Examples

A Montreal hair salon missed three quarterly filings and faced $2,500 in interest.
A contractor filed GST returns but forgot QST filings—Revenu Québec seized client payments.
A start-up claiming ITCs without valid invoices was reassessed and had refunds denied.

Lesson: file accurately, keep all receipts, and never ignore a Revenu Québec notice.

Mackisen Strategy

At Mackisen CPA Montreal, we simplify your filing process through:

1. Monthly or quarterly reconciliation of GST/QST accounts.

2. CPA review of ITCs and ITRs before submission.

3. Automated reminders and submission tracking.

4. Secure archiving of confirmation receipts for six years.

We also assist clients with past-due returns, penalty relief requests, and audit representation.

Common Questions

Do I need to file if I had no revenue?
Yes. File a nil return. Failing to file counts as default and triggers automatic interest.

Can I file for both GST and QST at once?
Yes. Mon dossier allows combined filing for both accounts.

What if I made a mistake?
You can amend returns online or through a CPA. Keep documentation for all corrections.

How long do I keep records?
Six years after the end of the fiscal year.

Can I delegate my accountant?
Yes. Authorize Mackisen CPA through the My Account for Representatives portal.

Compliance Checklist

Do

• File by each deadline.

• Maintain accurate sales and purchase records.

• Keep proof of remittances and confirmations.

• Consult a CPA for ITC/ITR eligibility.

• Separate GST/QST funds from operating cash.

Don’t

• Ignore Revenu Québec correspondence.

• File late or skip periods.

• Mix personal and business transactions.

• Claim tax credits without invoices.

Why Mackisen

Mackisen CPA Montreal provides complete GST/QST filing, reconciliation, and audit-defense services for businesses across Quebec. Our CPA auditors and tax specialists ensure every filing is precise, compliant, and optimized for your cash flow.