The CRA thinks you should be registered for GST/HST. Now what?

Reviewed by EverStone CPA · August 2026

Quick answer: A registration compliance letter means the CRA has data — usually your own income tax filings — suggesting your taxable revenues crossed the registration threshold, and it is asking you to register or explain. The dangerous part is timing: registration obligations arise when the threshold was crossed, not when you get around to it, so the letter is really about a start date. Respond with the facts; do not let the date default to the CRA’s guess. Our registration guide covers the mechanics.

How they knew

Your T1 or T2 reports revenue. The GST system knows whether that revenue has a registration attached. When the first says “business income” and the second says “no registrant”, a letter is generated. This is matching, not surveillance — and it means the response has to reconcile with what you already filed.

Why the start date is the whole game

If the threshold was crossed, you were required to register from that point — and tax was collectible on taxable sales from then, whether or not you charged it. A wrong start date can turn into remitting tax you never collected. So the response is a dated revenue walk-through: when the threshold test was met, month by month, from your own records — not a shrug that accepts whatever period the CRA proposes.

If you genuinely were not required

Not all revenue is taxable revenue, and not all activity is commercial activity. If your revenues are exempt, zero-rated in ways that change the analysis, or below the threshold on the correct test, say so with the numbers. The letter is a question, and “no, and here is why” is an available answer when it is true.

If you should have registered a while ago

This is recoverable and common. Registration can be effective from the correct past date, returns get filed for the intervening periods, and input tax credits from those periods offset some of the liability. What decides how expensive it is: acting before deadlines in the letter pass, and getting the dates right. This is a situation where an hour of advice before responding routinely pays for itself — email us the letter first.

Book a free consultation Email us your question

Fastest first step: email what you’re facing to info@everstonecpa.com — reply within one business day, and we book the consult from there.

General information, not tax advice. The document in your hand and its own dates govern.

Common questions

What is the registration threshold?+

It is a rolling test on taxable supplies, and the precise mechanics matter more than the headline number — which is why this page sends you to the registration guide rather than quoting a figure that gets misapplied. The letter itself tells you the CRA believes the test was met.

Do I owe GST on sales where I never charged it?+

If registration was required at the time, the tax was collectible whether or not it was charged — that is why the start date is the whole fight. It is also why responding with your own dated numbers beats accepting a proposed period.

Can I just register today and move on?+

Registering "from today" when the obligation arose earlier does not close the earlier periods — it leaves them open with no filings attached. The clean fix is registration from the correct date with the catch-up returns behind it.

Is this the same as the Voluntary Disclosures Program?+

No — but they can interact. Once the CRA has written to you about the matter, VDP eligibility for it changes, which is exactly why the order of operations deserves advice before any response goes in.

Email the letter before you register anything

The start date decides the cost. Get it read first — reply within one business day.

Email us — info@everstonecpa.com Or book directly