29 July 2026
When Should You Register for GST/HST?
Most Canadian businesses can ignore GST/HST until they cross a single number — and then the rules arrive all at once, with a deadline attached. Knowing when register GST Canada rules require you to act protects you from collecting tax you never charged and paying it out of your own margin. This guide covers the $30,000 small supplier threshold, exactly when you stop being exempt, and the cases where registering early is the smarter choice.
The small supplier rule in one paragraph
You are a small supplier — and do not have to register — while your worldwide revenue from taxable supplies, together with that of your associates, stays at $30,000 or less in a single calendar quarter and over the last four consecutive calendar quarters. Cross that line and registration becomes mandatory, on a timetable that depends on how you crossed it.
How the $30,000 threshold is actually measured
The threshold trips up business owners because it is not a calendar-year test and it is not based on profit. Three details matter.
Revenue, not profit
It is total revenue before expenses from your worldwide taxable supplies — including zero-rated sales. Your costs are irrelevant to the test.
A rolling four-quarter test
You test the last four consecutive calendar quarters — a rolling twelve months — as well as any single quarter on its own. Not your fiscal year.
Associates count too
Revenue of associated businesses is included. You cannot stay under the threshold by splitting one business across several related entities.
Some amounts are excluded
The calculation excludes goodwill from the sale of a business, supplies of financial services, and sales of capital property.
Two ways to cross the threshold — and two different deadlines
This is the part most guides get wrong. The consequences depend entirely on whether you blew past $30,000 in one quarter or crept over it across four.
| How you exceeded it | When you stop being a small supplier | Effective date of registration | Deadline to register |
|---|---|---|---|
| Over $30,000 in a single calendar quarter | Immediately — on the sale that put you over | No later than the day of that sale. You must charge GST/HST on that sale itself | Within 29 days of the effective date |
| Over $30,000 across four consecutive quarters, but not in any single quarter | At the end of the month following that quarter | The day of your first taxable supply after you stop being a small supplier | Within 29 days of the effective date |
| Still at or under $30,000 | You remain a small supplier | Voluntary — usually the day you request the account, or up to 30 days earlier | No deadline |
Who must register regardless of revenue
The small supplier exemption does not apply to everyone. Some businesses must register from their very first dollar.
When registering voluntarily makes sense
Staying under the threshold is not automatically the right answer. Registering before you have to lets you claim input tax credits (ITCs) — recovering the GST/HST you pay on business purchases. That can be worth real money.
You are buying a lot up front
Startups purchasing equipment, inventory, or professional services pay GST on all of it. Registering lets you recover that tax instead of absorbing it.
Your customers are businesses
Registered business customers claim back the GST/HST you charge, so it costs them nothing. Adding tax to your invoices does not make you less competitive.
You make zero-rated supplies
If you export or sell zero-rated goods, you charge tax at 0% but can still claim ITCs on your costs — often producing a refund.
You are about to cross anyway
If growth will take you past $30,000 within months, registering early avoids the scramble and the risk of an uncharged sale.
The trade-off is real, though. Registration means charging tax, filing returns on schedule, and keeping records to support your claims. If you sell mainly to individual consumers, adding 5% GST in BC makes you more expensive to them — they cannot recover it. Weigh the ITC recovery against that pricing effect and the ongoing GST/HST filing obligation.
What happens after you register
Registration assigns you a reporting period based on your taxable supplies. You can usually elect to file more often than required, but not less.
| Annual taxable supplies | Assigned reporting period | Optional periods you may elect |
|---|---|---|
| $1,500,000 or less | Annual | Monthly or quarterly |
| More than $1,500,000 up to $6,000,000 | Quarterly | Monthly |
| More than $6,000,000 | Monthly | None |
Electronic filing is required for most GST/HST registrants for reporting periods beginning on or after January 1, 2024. In British Columbia you charge 5% GST; BC's 7% PST is a separate provincial tax with its own registration rules.
Track revenue every quarter
Check your rolling four-quarter total at the end of each calendar quarter — March 31, June 30, September 30, and December 31 — so the threshold never arrives unnoticed.
Register and start charging
Once registered, charge GST/HST from your effective date and show your business number on invoices so customers can support their own ITC claims.
Choose your accounting method
Many small service businesses save money with the Quick Method, available to registrants under the $400,000 threshold. See the GST/HST Quick Method in BC to check whether it fits.
File and remit on time
Set aside the tax you collect — it was never your money — and file every period, including nil returns. Our GST/HST filing deadline guide covers the dates.
Frequently asked questions
Not sure whether you have crossed the threshold?
J. Wang Chartered Professional Accountant reviews your revenue against the when register GST Canada rules, handles the registration, and keeps your filings on schedule.
