Most Canadian businesses must register for the GST/HST once taxable revenue goes over $30,000, either in a single calendar quarter or over the previous four consecutive quarters. Below that, the CRA treats you as a small supplier and registration is optional (figures as of October 2026, in Canadian dollars).
The single-quarter rule is the one that catches fast-growing businesses. Cross the line in one quarter and the CRA says you have to charge GST/HST on the very sale that took you over it.
The small supplier test, in the CRA's words
| If | Then | Effective date of registration |
|---|---|---|
| You don't exceed $30,000 over four consecutive calendar quarters | You're a small supplier; registration is voluntary | Usually the day you request it, or up to 30 days before |
| You exceed $30,000 in a single calendar quarter | You're no longer a small supplier and must charge GST/HST on the supply that took you over | No later than the day of that supply |
| You exceed $30,000 over the previous four or fewer quarters, but not in one quarter | You stop being a small supplier at the end of the month after the quarter you went over | No later than the day of your first supply after that |
The CRA's own worked example is a candle business that made $29,000 across four quarters in its first year: still a small supplier, because it never passed $30,000. One bigger quarter would have changed that.
What counts towards the $30,000
- Include: taxable sales, leases and other supplies, including zero-rated supplies, and the taxable supplies of all your associates.
- Leave out: exempt supplies, financial services, sales of capital property and goodwill from selling the business.
- New business? The CRA says you can give a reasonable estimate of your income for the year when you register.
The associates line matters if you run more than one business: their taxable supplies count towards your threshold too.
Businesses that must register from day one
Taxi operators and commercial ride-sharing drivers must register even if they're small suppliers; their registration takes effect the day they start supplying taxable passenger transportation. Charities, public institutions, public service bodies and non-residents have their own small supplier rules, so check the CRA page for your category rather than applying the $30,000 rule automatically.
Registering voluntarily
You can register before you have to. Registration usually takes effect on the date of your request, or up to 30 days earlier. The catch: the CRA says that when you register voluntarily you may need to stay registered for at least one year before you can cancel. If you've been required to register, or have been charging GST/HST, for more than 30 days before registering, there's a separate process to backdate registration by more than 30 days.
What you'll need to register online
- Personal details for the person submitting the request: last name, Social Insurance Number, date of birth and the postal code of their home address.
- Your business information.
- Your fiscal year: usually the same as your income tax year, which for individuals, certain trusts and many partnerships is the calendar year. A corporation with a non-calendar tax year can elect a calendar year for GST/HST.
- An estimate of revenue if you're just starting.
Your GST/HST account sits alongside your business number. If you haven't got one yet, my guide to the CRA business number explains it, and if you're in Ontario, here's how to register a business in Ontario before you get to the tax side.
A quick self-check before you hit the limit
- Add up taxable sales, leases and other supplies for each of the last four calendar quarters, including zero-rated ones.
- Add the taxable supplies of any associated businesses.
- Take out exempt supplies, financial services, capital property sales and goodwill.
- If any single quarter is over $30,000, you must already be registered and charging from the sale that crossed it.
- If the four-quarter total is over $30,000, you stop being a small supplier at the end of the month after that quarter.
- If you're close, consider registering voluntarily so there's no gap.
Run this every quarter end. It takes minutes with decent bookkeeping, and the CRA's single-quarter rule means an annual check is too late.
Changing your fiscal year later
If your corporation uses a non-calendar fiscal year for both income tax and GST/HST and then changes to a different non-calendar year for income tax, the CRA says to tell it as soon as possible so your GST/HST fiscal year changes too. Partnerships and individuals who want a non-calendar tax year need CRA approval first.
My verdict
Track your taxable revenue quarter by quarter, not just by year, and set an alert well below $30,000. If one big contract could push a single quarter over, register before it lands so you can charge GST/HST on that invoice from the start. Registering voluntarily early is often tidier, as long as you're happy to stay registered for at least a year.
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Frequently asked questions
When must I register for GST/HST?
When your taxable revenue goes over $30,000 in a single calendar quarter or over four consecutive calendar quarters. Below that you're a small supplier.
What is a small supplier for GST/HST?
A business whose taxable supplies don't exceed $30,000 over four consecutive calendar quarters. Small suppliers don't have to register.
Can I register for GST/HST voluntarily?
Yes. It usually takes effect on the date of your request or up to 30 days before, but you may need to stay registered for at least one year.
Do taxi and ride-share drivers need to register for GST/HST?
Yes. The CRA says taxi operators and commercial ride-sharing drivers must register even if they're small suppliers.
What counts towards the $30,000 threshold?
Taxable sales, leases and other supplies, including zero-rated supplies, plus the taxable supplies of your associates. Exempt supplies and financial services don't count.
Does a new business need to know its revenue to register for GST/HST?
No. The CRA says a business that's just starting can give a reasonable estimate of its income for the year.
Do exempt supplies count towards the small supplier limit?
No. Exempt supplies, financial services, sales of capital property and goodwill from selling the business are left out.
Can I backdate my GST/HST registration?
Up to 30 days in the normal process. To backdate more than 30 days, the CRA has a separate request process.
