The $30,000 threshold, read the way the CRA reads it.
Everyone knows the number. What catches businesses is the window it is measured over, the two different ways of crossing it — each with its own start date — and the fact that tax can be owed on sales where it was never charged.
Updated August 2026 · Reviewed by the VertAcc accounting team · Ottawa, Canada
The small-supplier test
You are a small supplier — not required to register for or charge GST/HST — while your total taxable revenues stay at $30,000 or less across four consecutive calendar quarters. It is a rolling four-quarter window, not a calendar year, and it counts worldwide taxable revenues including zero-rated sales, across you and your associates.
The two ways of crossing, and their different clocks
1. One big quarter
Exceed $30,000 within a single calendar quarter and you stop being a small supplier immediately — effective on the sale that put you over. That sale, and everything after it, is taxable. You then generally have 29 days to register.
2. The slow accumulation
Cross $30,000 over four consecutive quarters (but not in any single one) and you keep small-supplier status until the end of the month following that quarter. Your registration takes effect no later than your first sale after that grace period ends.
The dangerous scenario is the invisible crossing: steady growth trips the rolling window mid-year, nobody notices, and a year later the CRA registers the business retroactively — owing 13% on months of Ontario sales where it was never charged. Books that are current catch the crossing the quarter it happens.
Why registering early is often the better trade
Registration under the threshold is voluntary — and frequently smart. Registered businesses recover the GST/HST they pay on expenses through input tax credits: on equipment, software, rent, professional fees. A startup spending heavily before revenue arrives is leaving refunds unclaimed every unregistered quarter. The trade is the admin of filing returns — which is only a burden when the books behind them are.
After registration: the discipline
GST/HST you collect is not revenue — it is the CRA’s money moving through your account. The businesses that get hurt are the ones that discover their HST balance at filing time, after the cash has been spent. Our clients’ returns are reconciled to the books and tracked to their deadlines, so the balance is a number you watch, not a surprise you meet. The same discipline applies to payroll’s trust money — covered in its own guide.
The short version of working with us
VertAcc is an Ottawa accounting firm that writes its own software. Bookkeeping, tax, payroll and year-end run on a fixed monthly fee — no hourly meter, calls never billable, and the accounting platform is included with setup done free. If your books are behind or a deadline on this page is already past, that is ordinary work for us, not a judgement.