GST/HST Registration: When Do Small Businesses Have to Register?

You have to register for GST/HST once your business stops being a “small supplier”, which happens when your worldwide taxable supplies go over $30,000 in a single calendar quarter or over four consecutive calendar quarters. Once you cross that line, you have 29 days to register, and in Ontario you charge 13% HST on your taxable sales. Below $30,000, registration is optional, and registering voluntarily can make sense if you want to recover the HST you pay on business costs.

Here’s how the rules work in practice, with examples.

Who counts as a small supplier?

You are a small supplier if your total revenue from taxable supplies, before expenses, is $30,000 or less over the last four consecutive calendar quarters (or fewer, if you’re new) and you haven’t gone over $30,000 in any single quarter (CRA, when to register).

A few details trip people up:

• It’s worldwide. Sales to customers outside Canada count, including zero-rated supplies like most exports.
• Associates count too. If you control or are associated with other businesses, their taxable supplies are added to yours.
• Some revenue is excluded. Financial services, sales of capital property and goodwill from selling a business don’t count.
• Exempt supplies don’t count. Long-term residential rent and most health care services, for example, are exempt, so they don’t push you toward the threshold.

Calendar quarters are January to March, April to June, July to September and October to December, regardless of your fiscal year-end.

How does the single calendar quarter test work?

If your taxable supplies go over $30,000 within one calendar quarter, you stop being a small supplier immediately, on the sale that takes you over the threshold. You must charge GST/HST on that sale, and your effective date of registration is the day of that sale. You then have 29 days to register.

This test catches businesses that grow quickly or land one large contract. It’s worth watching your quarterly totals as you approach $30,000, because the consequence is immediate.

How does the four consecutive quarters test work?

Most small businesses cross the threshold gradually. If you go over $30,000 across your last four (or fewer) consecutive calendar quarters, but never within a single quarter, you get a short grace period. You stop being a small supplier at the end of the month following the quarter in which you went over. You then start charging GST/HST on your first sale after that date, which is your effective date of registration, and you must register within 29 days.

What if you missed the registration date?

It happens more often than you’d think, usually because an owner was tracking sales by fiscal year instead of by calendar quarter. Once you’re required to be registered, the CRA treats you as owing GST/HST on your taxable sales from your effective date, whether or not you actually charged it. If you didn’t collect it from customers, the tax generally comes out of your own margin, and penalties and interest can be added on top.

The fix is to register as soon as you notice, work out your correct effective date, and file returns back to that date. If the amounts are significant, get advice first. It is often possible to go back to business customers for the missing HST, but consumers are much harder to recover from.

Who has to register even below $30,000?

The small supplier exception doesn’t apply to everyone. Self-employed taxi operators and commercial ride-sharing drivers must register for GST/HST from the day they start providing rides, regardless of how much they earn. Certain non-residents, such as those who sponsor conventions or sell admissions to events in Canada, also have special rules.

If you’re unsure whether a special rule applies, check before you start operating. A missed registration can mean paying the HST you should have charged out of your own pocket.

Should you register for GST/HST voluntarily?

You can register voluntarily at any time, even with sales well under $30,000 (CRA, voluntary registration). Once registered, you must charge, collect and remit GST/HST on your taxable sales, but you can also claim input tax credits (ITCs) to recover the GST/HST you pay on business purchases and operating costs.

Registering voluntarily tends to make sense when:

• Your customers are mostly businesses. HST-registered customers recover the HST you charge them through their own ITCs, so it doesn’t make you more expensive.
• You have significant startup costs. Equipment, a leasehold fit-out or inventory can carry a lot of HST that you’d otherwise lose.
• You expect to cross $30,000 soon. Registering early avoids a mid-year scramble and a price change for customers.
• You want to look established. Some clients prefer to deal with registered suppliers.

It may not make sense if you sell mainly to consumers who can’t claim ITCs, since charging 13% HST effectively raises your prices or cuts your margin.

What rate do you charge in Ontario?

Ontario businesses charge 13% HST, made up of the 5% federal GST and 8% provincial portion (CRA rates). The rate generally follows where the supply is made, so a sale to a customer in another province can carry a different rate. Our HST calculator helps you work out tax-in and tax-out amounts quickly.

Some supplies are zero-rated, meaning they’re taxable at 0%. You don’t charge HST, but you can still claim ITCs on related costs. Basic groceries, most prescription drugs and most exports fall into this group.

How often will you file GST/HST returns?

The CRA assigns your reporting period based on your annual taxable supplies (CRA, change your account):

Filing and payment deadlines depend on that period (2026 tax deadlines):

• Monthly and quarterly filers: one month after the end of each period.
• Annual filers: three months after the fiscal year-end.
• Self-employed individuals filing annually with a December 31 year-end: file by June 15, but pay by April 30.

Many small businesses choose quarterly filing, even when they could file annually, because it keeps the HST owing from building into one large bill. If your sales are modest and your expenses are low, the Quick Method may also save you money. See our comparison of the Quick Method vs. the regular method.

The figures in this article are current as of October 2026; the November 5, 2026 federal budget could change some of them.

How MNJ CPA can help

We help Ontario businesses work out when they need to register, set up their GST/HST accounts, choose a reporting period and file accurate returns. If you’re close to the $30,000 mark or have already passed it, our GST/HST services can help, or you can reach out with your questions.