How to File a GST Return Online in Canada: Quick Start Guide

Introduction

Filing your GST/HST return online is the fastest way to stay compliant, avoid penalties, and keep your cash flow predictable. This quick-start guide from Mackisen CPA Montreal walks you through exactly what to prepare, where to file, how to enter the numbers, and how to remit payment—step by step—so you can file with confidence today.

Legal and Regulatory Framework

GST/HST is governed by the Excise Tax Act (federal). If you are registered, you must file returns for every reporting period—even if you had no sales. CRA can assess interest and penalties for late filing or late payment. Keep all GST/HST records (invoices, receipts, reconciliations) for at least six years.

Reporting Frequencies and Deadlines

Monthly and quarterly filers: return and payment due one month after the period end.
Annual filers (most small businesses): return due three months after fiscal year-end; payment due one month after year-end.
Annual filers who are individuals with a December 31 year-end: you may have until June 15 to file, but payment is still due April 30.

Learning Insight

File even if you cannot pay in full. Filing on time minimizes penalties and allows payment arrangements. Not filing at all triggers automatic assessments and collections.

What You Need Before You File

1. CRA login: My Business Account (business owner) or Represent a Client (your CPA).

2. Your reporting period (monthly, quarterly, or annual) and the period dates.

3. Sales summary: total taxable sales (including zero-rated).

4. GST/HST collected from customers.

5. Input Tax Credits (ITCs): GST/HST paid on eligible business purchases.

6. Any instalments already paid for the period.

7. Banking set up for payment (online banking payee “CRA GST/HST”, pre-authorized debit, or CRA “My Payment”).

Learning Insight

Clean bookkeeping = faster filing. Reconcile bank accounts and sales tax control accounts before you file. This prevents re-assessments and preserves your ITCs.

Step-by-Step: File Your GST/HST Return Online

Step 1 — Sign in

Log in to CRA My Business Account. Choose your BN and select “GST/HST” then “File a return”.

Step 2 — Select the period

Confirm the period shown matches your books. If a period is missing or incorrect, verify your frequency settings before proceeding.

Step 3 — Enter line items

You’ll enter:

• Total sales and other revenue for the period (excluding exempt sales as required).

• GST/HST collected or collectible.

• ITCs you’re claiming for the period.

• Net tax = GST/HST collected minus ITCs.

If you had no activity, file a nil return.

Step 4 — Review and submit

Confirm calculations match your trial balance and sales tax reports. Submit the return and save/print the confirmation page or PDF.

Step 5 — Pay the balance

Pay immediately after filing to stop interest. Options:

• Online banking: add “CRA GST/HST” as a payee and use your BN RT account.

• Pre-authorized debit: schedule payment in My Business Account.

• CRA “My Payment”: pay by debit card directly from your bank account.

Record the payment in your books and keep the receipt with your GST file.

Frequent Errors to Avoid

• Missing a period or filing the wrong dates.

• Claiming ITCs without proper invoices/proof of payment.

• Using gross sales instead of required taxable amounts.

• Forgetting instalments already made.

• Filing late because books weren’t reconciled.

Learning Insight

If your software report doesn’t tie to the CRA lines, export to Excel and reconcile: Sales → Tax Collected → ITCs → Net Tax. Keep this worksheet in your audit binder.

Common Questions

Do I need to file if there were no sales?
Yes. Registered accounts must file every period. File a nil return to avoid penalties.

Can I amend a mistake after filing?
Yes. You can request an adjustment online. Keep documentation that supports any change.

What if I can’t pay in full?
File on time, then set up a payment arrangement with CRA. Filing late increases penalties and interest.

How do instalments work?
Large net-tax payers may be required to make instalments. Apply them on the return so your balance due is correct.

How long should I keep records?
Six years from the end of the last tax year they relate to.

Compliance Checklist

Do

• Reconcile bank, sales tax control, and AR/AP monthly.

• Retain invoices and payment proof for all ITCs.

• File by the deadline, even with a balance owing.

• Pay electronically and save the confirmation.

• Keep a period-by-period GST worksheet in your audit binder.

Don’t

• Mix personal and business purchases.

• Claim ITCs for non-business or missing-documentation expenses.

• Wait for CRA reminders.

• Ignore a balance due—interest compounds daily.

• Change frequencies without updating your books and reminders.

Mackisen Strategy

We set up a repeatable monthly close: reconcile → review ITC eligibility → export tax reports → file → pay → archive confirmations. For clients, we also configure reminders, monitor CRA mail, and prepare adjustment support files so audits are quick and low-stress.

Why Mackisen

Mackisen CPA Montreal files thousands of GST/QST/GST-HST returns for Quebec and Canadian businesses. We build audit-ready workflows, train your team, and step in as needed—from setup to full outsourcing—so returns are accurate, on time, every time.