Short answer: if your business earns more than $30,000 in taxable revenue, you almost certainly have to. Below that, you get to choose — and the choice is worth thinking about rather than defaulting to "no".
You must register for GST/HST once your worldwide taxable revenue passes $30,000. Two different tests trigger it, and people usually only know the first:
That second test catches people with one big project. A consultant who bills $8,000 a quarter all year is fine. The same consultant who lands a single $35,000 contract in the spring is not.
The threshold counts revenue, not profit, and it counts your worldwide taxable sales — not just the Canadian ones, and not just the ones from your biggest client.
There is a persistent belief that services are somehow different from products, or that invoicing a single company as a contractor means the rules do not apply. They do. Consulting, design, bookkeeping, trades, IT work — these are taxable supplies, and the $30,000 test applies exactly as it would to someone selling goods.
What changes is which tax you charge, which depends on where your client is, not where you are. Send an invoice to an Ontario client and you charge 13% HST even if you are sitting in Calgary. Provinces with HST run 13–15%; the rest are 5% GST, with provincial sales tax handled separately where it applies.
Voluntary registration is allowed under $30,000, and for some businesses it is the better call.
| Register early if | Wait if |
|---|---|
| You buy a lot — equipment, software, subcontractors — and want the input tax credits back | Your customers are consumers who cannot claim it back, and price sensitivity matters |
| Your clients are businesses; they claim the tax back and will not notice it | Your costs are minimal, so there is little to recover |
| You are near the threshold and would rather not track it week to week | You genuinely want less paperwork this year |
The catch is that registration is a commitment: once registered you must charge on every taxable sale, file returns on schedule even when there is nothing to report, and stay registered for at least a year.
This trips people up because two of them mean "no tax on the invoice" but behave completely differently:
If everything you sell is exempt, you cannot register and cannot recover the tax you pay on your own costs. Worth confirming before you assume you are simply under the threshold.
Not registering on time, and only noticing later. The obligation starts when you cross the threshold, not when you get round to registering — so the CRA can assess the tax you should have collected on those sales, plus interest and penalties. Collecting it from clients months after the fact is a conversation nobody enjoys.
If you are anywhere near $30,000, watch the rolling four-quarter total rather than the calendar year. It is one number, and checking it monthly takes a minute.
General information for Canadian businesses, current as at 2026 and not tax advice. Thresholds, rates and the exempt list change — confirm with the CRA or your accountant before deciding whether to register.