When Does Your Ontario Small Business Need to Register for HST/GST?

One of the most common compliance questions from new Ontario business owners is: when do I have to start collecting and remitting HST? Charging HST before you're required to can feel premature; missing the registration deadline can trigger penalties and back-remittances. Getting this right from the start protects your business — and sometimes registering early is actually advantageous.

In Ontario, the federal Goods and Services Tax (GST) and the Ontario provincial harmonized component are collected together as HST (Harmonized Sales Tax). The combined rate as of writing is a set percentage; verify the current combined rate with the CRA because it can change. This article explains the registration rules, the small supplier exemption, the concept of input tax credits, and when voluntary early registration makes financial sense.

The Small Supplier Threshold

You do not have to register for HST if you are a small supplier — broadly, a business whose total taxable revenues (before HST) have not exceeded a defined dollar threshold in the last four consecutive calendar quarters or in a single calendar quarter.

As of writing, the small supplier threshold is a specific annual figure set by the federal Excise Tax Act. Confirm the current threshold with the CRA or your accountant, because it has not always been indexed to inflation.

Once your revenues exceed the threshold, you are no longer a small supplier. At that point:

• You must register for an HST account with the CRA.
• You must begin collecting HST from customers on taxable supplies.
• You must file HST returns and remit the tax you collected.

The registration deadline is typically within a set number of days of the quarter in which you exceed the threshold — confirm the exact deadline with the CRA.

What Counts Toward the Threshold

The threshold calculation includes taxable supplies — essentially, most commercial goods and services in Canada that are subject to HST at the standard rate or at the zero rate (discussed below). You add up revenue from all your businesses and those of any associated persons or corporations.

It does not include:

• Supplies that are exempt from HST (e.g., most residential rent, many health-care services, most educational services, certain financial services)
• Sales of capital property used in your business (like selling a business vehicle)

If your business is incorporated and you personally carry on a separate business as well, the revenues of both may need to be combined. The CRA's rules here are detailed; ask your accountant.

Exempt vs. Zero-Rated: An Important Distinction

Not all supplies escape HST the same way:

• Exempt supplies: HST does not apply, and you cannot claim input tax credits (ITCs) on expenses related to those supplies. Examples: most residential rents, certain health and dental services.
• Zero-rated supplies: HST technically applies at a 0% rate, meaning no HST is charged to the customer, but the supplier can still claim ITCs on related expenses. Examples: basic groceries, prescription drugs, most exports.

If your business makes primarily exempt supplies (e.g., a residential landlord), registering for HST provides little benefit even above the threshold — and may not be required at all depending on the nature of your supplies. If your business makes zero-rated supplies, registering early makes more sense because you can recover ITCs.

Input Tax Credits: The Hidden Benefit of Registration

When you are registered for HST, you can claim input tax credits (ITCs) — refunds of the HST you paid on business expenses. For a business that spends significantly on supplies, equipment, professional fees, rent, or other taxable inputs, ITCs can be a meaningful cash recovery.

This is the main reason many small businesses voluntarily register even before they hit the threshold. If your clients are businesses (B2B sales), charging them HST is typically neutral — they reclaim it via their own ITCs. But you start recovering HST on your own expenses immediately.

If your clients are consumers (B2C), charging HST may reduce your competitive appeal or require you to raise prices. Weigh this carefully before registering early.

Voluntary Registration: When It Makes Sense

You may register voluntarily at any time, even as a tiny startup. Consider doing so if:

• Your business spends significantly on HST-taxable inputs (equipment, software, professional services, lease payments)
• Your customers are primarily other businesses that expect to receive HST invoices and claim ITCs themselves
• You are approaching the threshold and want to avoid a scramble to register mid-quarter
• You are a new business with significant startup costs and want to recover HST on those costs immediately

Once you are registered, you must collect and remit HST on all taxable supplies — you cannot selectively charge it. Registration is generally irrevocable for the short term (there are rules around de-registration).

Filing Periods and Remittance

Registered businesses file HST returns annually, quarterly, or monthly, depending on their annual taxable revenues. The CRA assigns your initial filing period based on your revenue at registration. You can request a change.

The net amount you remit is HST collected minus ITCs claimed. If your ITCs exceed the HST collected (common for startups with large purchases and small revenues), you receive a refund.

Missing remittance deadlines triggers interest and penalties that can add up quickly — get organized with your accountant or bookkeeper as soon as you register.

Frequently asked questions