GST/HST Filing for Canadian Small Businesses: A Practical Guide

There's a common source of confusion among Canadian small business owners: the difference between registering for GST/HST and filing your GST/HST returns. Registration is a one-time step — you get a GST number and an obligation to collect tax. Filing is the ongoing obligation — submitting returns and remitting the net tax you owe (or claiming a refund). This guide focuses on the filing side: what to report, how often, and how to avoid the most common mistakes.

If you haven't registered yet or aren't sure whether you need to, read our guide on GST/HST registration in Canada first.

How Often Do You Need to File?

Your filing frequency is determined by your annual taxable revenue. The CRA assigns a default frequency when you register, but you may be able to elect a different frequency in some cases.

Annual Taxable Revenue	Default Filing Frequency	Return Due Date
Under $1.5 million	Annual	3 months after fiscal year-end
$1.5 million – $6 million	Quarterly	1 month after each quarter-end
Over $6 million	Monthly (mandatory)	1 month after each month-end
Voluntary registrants (any revenue)	Annual (default)	3 months after fiscal year-end

Annual filers with revenue between $1.5M and $6M can elect to file quarterly instead. Businesses under $1.5M can elect to file monthly or quarterly if they prefer more frequent cash flow (useful if you're regularly in a refund position due to high input tax credits).

Two Methods to Calculate Your Net Tax

Regular Method (Most Common)

Under the Regular Method, your net tax is straightforward:

Net Tax = Total GST/HST Collected − Input Tax Credits (ITCs) Claimed

If your net tax is positive, you remit the balance to the CRA. If it's negative (you paid more GST/HST on purchases than you collected from customers), the CRA owes you a refund.

Input Tax Credits are the GST/HST you paid on business purchases and expenses. You can claim ITCs for most business expenses — supplies, equipment, utilities, professional fees. Meals and entertainment are generally limited to 50%. For a detailed breakdown of what qualifies and the documentation requirements, see our article on Input Tax Credits in Canada.

Quick Method (Available for Eligible Businesses)

The Quick Method is an optional simplified approach available to most businesses with annual taxable revenues under $400,000. Instead of tracking every ITC individually, you remit a fixed percentage of your gross sales (including GST/HST), and keep the difference.

The remittance rates vary by business type and province. For example, a service business in Ontario (13% HST) using the Quick Method remits 8.8% of gross revenue (including HST) to the CRA. The remaining 4.2% effectively stays with the business.

The Quick Method can be significantly advantageous for service-based businesses with few taxable inputs (software subscriptions, consulting businesses, professional services). Businesses that buy a lot of taxable goods generally do better under the Regular Method where they can claim full ITCs.

What Goes on the GST34 Return

The GST/HST return (Form GST34) is straightforward once you know what each line represents:

• Line 101 — Total sales and other revenue: Your total taxable sales for the period, including zero-rated sales. Do not include exempt sales or out-of-scope amounts.
• Line 103 — GST/HST collected or collectible: The total GST/HST you charged to customers during the period, whether or not they've paid you yet (accrual basis).
• Line 106 — Input Tax Credits claimed: The GST/HST you paid on eligible business expenses during the period.
• Line 109 — Net tax: Line 103 minus Line 106. If positive, you owe this amount. If negative, the CRA owes you a refund.

How to File Your GST/HST Return

There are four ways to submit your GST34 return:

1. NETFILE: File electronically through the CRA's My Business Account portal at canada.ca. This is the fastest option and you receive immediate confirmation.
2. Through your bookkeeper or accountant: Your authorized representative can file on your behalf using the CRA's Represent a Client system.
3. Through your accounting software: Many cloud accounting platforms integrate directly with the CRA for GST/HST NETFILE.
4. Paper GST34: The CRA mails paper returns to businesses that elected paper filing. This is the slowest method and not recommended — processing times can be 4–6 weeks.

What Happens After You File

If You Owe a Balance

The balance is due on the same day as your return. If you miss the payment deadline, the CRA charges interest at the prescribed rate (currently compounded daily) from the day after the due date. A late-filing penalty also applies: 1% of the balance owing, plus 25% of that amount for each additional month late, up to a maximum of 12 months. Even if you can't pay the full amount, file on time to avoid the late-filing penalty — then set up a payment arrangement with the CRA.

If You're Owed a Refund

If your ITCs exceed the GST/HST you collected (common for businesses with large capital purchases, or in slow revenue periods), the CRA issues a refund. Electronically filed returns are typically processed within 21 business days. Refunds may be applied against any other CRA balance you have before the remaining amount is sent to you.

Common GST/HST Filing Errors

These are the mistakes our team sees most often:

• Wrong reporting period: Filing a quarterly return with monthly figures, or including transactions from outside the reporting period. Always match the transactions in your return to the exact start and end dates of the reporting period.
• Missing zero-rated sales on Line 101: Zero-rated sales (exports, basic groceries, certain medical supplies) are still taxable sales — they're just taxed at 0%. They must be reported on Line 101 even though no GST/HST is collected.
• Claiming personal expenses as ITCs: Only GST/HST paid on expenses that are for commercial use can be claimed. Personal expenses mixed with business expenses must be prorated — and the personal portion is not claimable.
• Not filing when you owe $0: Even if your net tax is zero for a period, you must still file a nil return by the due date. Failure to file results in a late-filing penalty.
• Forgetting to file after ceasing operations: If you close your business or deregister for GST/HST, a final return covering the period up to the deregistration date must be filed within one month.

Our GST/HST filing service handles your returns end-to-end — accurate calculations, timely filing, and proactive monitoring of your account balance so you're never caught off guard.