Every Canadian business crosses the same line eventually: the point where charging GST/HST stops being optional. The line sits at $30,000 in revenue — but how that number is measured trips up more owners than the number itself. Here's how the small-supplier rule actually works.
You're a "small supplier" — exempt from mandatory registration — while your worldwide taxable revenues stay at or under $30,000 across four consecutive calendar quarters. Two details in that sentence do all the damage.
First, four consecutive calendar quarters is a rolling measurement, not a calendar year. A strong twelve months that straddles two tax years can cross the line even though neither year looks remarkable on its own.
Second, crossing it in a single quarter changes the timing: exceed $30,000 within one calendar quarter and you lose small-supplier status immediately — you're required to start charging on the sale that crossed the line, not at some polite future date. Grow gradually and there's a short grace window; grow suddenly and there isn't.
The expensive failure mode is not watching. Businesses that cross the threshold unknowingly and keep invoicing without tax are still liable for the GST/HST they should have collected — out of their own pocket. This is one of the quiet arguments for monthly bookkeeping: a rolling four-quarter revenue total is trivial to watch when the books are current and invisible when they aren't.
The threshold counts taxable supplies — which includes zero-rated sales like exports and basic groceries, even though the rate charged on them is zero. What doesn't count: exempt supplies. Long-term residential rent is the big one for our real estate clients — a landlord with substantial residential rental income may never be required to register, because that revenue sits outside the system entirely. Financial services and most health care services are similarly exempt.
The taxable-versus-exempt classification of your particular revenue is worth confirming early, because everything downstream depends on it.
Here's the counterintuitive part: voluntary early registration is sometimes the smart move. Registrants can claim input tax credits — recovering the GST/HST they pay on business expenses. A business in startup mode, spending on equipment and services while revenue ramps up, may be leaving real money unclaimed by staying unregistered.
The trade-offs: you must charge tax from registration onward (a consideration if your customers are consumers who can't recover it — less of one if they're businesses that can), and you take on filing obligations. For businesses selling mostly to other registrants, early registration is frequently a straightforward win.
The mindset shift that saves registrants from grief: GST/HST you collect was never your money. You're holding it in trust for the CRA until your return is due, and spending it on operations is the classic small business cash flow trap — it feels like revenue for months, then becomes a debt with the government's collection powers behind it. The fix is the same boring discipline as tax instalments: a separate account, funded with every deposit, untouchable.
The rate you charge generally follows where your customer is, not where you are — HST provinces, GST-plus-provincial-tax provinces, and GST-only territories all differ. For anyone selling across provincial lines, place-of-supply rules decide which rate applies to each invoice, and your invoicing setup needs to handle that from day one of registration.
The takeaway: the $30,000 threshold is simple; the measurement, the timing, and the trust obligation are where businesses get hurt. If you're approaching the line or suspect you've already crossed it, book a free consultation and we'll sort out where you stand.
This post is general information, not tax advice for your specific situation.
