GST/HST registration: when the clock actually starts

GST/HST registration becomes mandatory once your taxable revenue passes the small-supplier threshold, measured across four consecutive calendar quarters. The part that costs people money is that crossing the threshold and starting to charge are two different dates, and the second one arrives on a schedule set by the legislation rather than by when you get around to it. Below the threshold, registering is optional — and for an owner whose customers are other businesses, registering early is usually the cheaper choice, because input tax credits, the GST/HST you paid on your own purchases, only start flowing from the day your registration takes effect.

The threshold is a fixed dollar amount. It is not reproduced here, because the figure matters less than the two tests that apply it, and the tests are what owners get wrong.

Two tests, and only one of them gives you warning

The four-quarter test is the one people know about. At the end of each calendar quarter, total your taxable revenue for that quarter and the three before it. If that rolling total is over the threshold, you have stopped being a small supplier. It runs on calendar quarters, not on your fiscal year, so the crossing rarely lands anywhere near your year-end. It also runs across associated businesses rather than one company at a time, which means a second corporation does not reset the count.

The second test runs on a single quarter, and it is the one that catches people. If your taxable revenue in one calendar quarter alone exceeds the threshold, you stop being a small supplier at that moment — not at quarter end, at the supply that took you past it. One large contract can do this to a business that looked like it had a year of runway. That invoice carries tax.

One group gets neither test. Someone operating a taxi business registers from the first fare, at any revenue level. Whether that category reaches drivers carrying passengers for a ride-hailing platform, and how delivery-only work is treated, is worth confirming rather than assuming if you do both.

The gap between crossing and charging

Crossing the threshold does not make you a registrant that afternoon. Under the four-quarter test you keep small-supplier status until the end of the month following the quarter in which you crossed. Everything you bill in that window stays untaxed, permanently. From the day after, your taxable supplies carry tax, you are required to apply for a number within a window the legislation sets, measured in days from that first taxable supply, and the effective date of your registration is that day — not the day the CRA opens the account, which is usually later.

Under the single-quarter test there is no grace month at all. The supply that crossed the threshold is itself taxable.

Two dates get confused with the one that matters. The governing date is when the supply is made, not when the invoice is paid, and not when your application is processed. And tax you charge is tax you owe: put GST/HST on an invoice before your registration takes effect and you still have to remit it. The CRA does not treat it as yours to keep.

A consultant crosses the threshold in August

Illustrative, dates only, December 31 year-end. One corporation, no associated companies, Canadian corporate clients, revenue climbing steadily for two years.

Her rolling four-quarter total — last year’s fourth quarter plus this year’s first three — passes the threshold partway through August. The test is applied at quarter end, so the crossing is recorded on September 30. She stays a small supplier through October 31. Her August, September and October invoices carry no tax, and they never will.

From November 1 she charges on everything. She applies for the number, her effective date is November 1, and her November invoices show the tax and her registration number. Purchases made from that date carry recoverable credits; everything she bought before it does not. For a consultant that is software, a laptop and professional fees. For a retailer it would have been a season of inventory — which is why a rule exists letting a new registrant claim credits on inventory and capital property still on hand at the effective date.

Her first reporting period runs November 1 to December 31 — the effective date to the fiscal year-end. Filing annually, that return is due three months after year-end, March 31. The deadline table has the rest.

Change one fact. Suppose a single contract signed in July had, on its own, put one quarter’s billings past the threshold. No grace month, no October runway. The invoice that crossed it carries tax, and the client either receives a bill with tax added or a bill she has to eat.

Registering before you have to

Voluntary registration below the threshold buys three things. Credits on start-up spending — equipment, software, legal and accounting fees, the build-out — start flowing before revenue does, which is why a business that spends before it sells often files for refunds in its first year. Your invoices stop changing mid-relationship, which matters more than it sounds when a client’s accounts-payable department has to re-approve a rate. And you stop watching a rolling total every quarter.

What it costs depends entirely on who buys from you. A registrant business customer claims the tax back, so your price to them is unchanged and the tax is a line on an invoice. A consumer cannot, so the tax is a real price increase you either pass on or absorb. The CRA generally allows a limited backdating window on a voluntary application, which matters if invoices have already gone out with tax on them.

Registration is also durable. You file every reporting period whether you billed anything or not, and there is a minimum period before a voluntary registration can be cancelled. One thing that does not carry over: a corporation is a separate person for GST/HST, so a number you held as a proprietor does not follow you in when you incorporate.

What registration puts on your calendar

• Charge and show it. Tax on every taxable supply, at the rate for where the supply is made, with your registration number on invoices at or above a documentary threshold. Which rate applies where is its own set of rules.
• File on the cadence the CRA assigns you. Frequency follows annual taxable supplies — annual, quarterly or monthly — and you can generally elect to file more often than assigned, which is what a business sitting in a refund position does.
• Remit or claim every period, including the nil ones. A period with no activity still has a return and a due date.
• Instalments, if you file annually and your net tax for the year passes a threshold.

Once you are registered, the quick method becomes the next election to test. It applies prospectively — you elect from a reporting period forward, never backward — so the question is which period you start from, and it gets re-tested every year rather than settled once. A named list of businesses cannot elect at all.

If you should have registered and didn’t

The CRA can register you effective the date you were required to be registered, then assess the tax you should have charged from that date forward. It collects that from you. It does not go back to the customers who were invoiced without it.

The position is recoverable but rarely cheap. Input tax credits for the same period are generally claimable, subject to a limit on how far back a credit can be claimed, so the net assessment is smaller than the gross tax. Registrant customers will often accept a corrected invoice, because the tax costs them nothing they cannot claim back. Consumers will not, and neither will a client whose project closed two years ago. On top of the tax sit interest running from each period’s due date and a late-filing penalty on returns filed after they were due — and each missed period carries its own dates, so a registration date two years back is not one late return.

If you suspect you crossed a while ago, that is a facts question rather than an article question. It turns on your quarterly revenue for the last few years and on what is still recoverable on the purchase side.

What Cadence does

We test the threshold at onboarding against your last four quarters rather than your last fiscal year, because those are different numbers and only one of them is the test. If you have already crossed, we establish the effective date, register you to it, and cost out the uncharged tax before the CRA does it for you. If you are close, we tell you which quarter you are likely to cross in and whether registering ahead of it is cheaper than waiting. Establishing the registration date and the filing cadence is part of onboarding on every engagement, and the quick-method test runs at the same time so the election is tested in your first year rather than a year late; the returns themselves are GST/HST and payroll work, scoped at the estimate.