Do I Have to Register for GST and QST?
You have to register for the GST and QST files as soon as your taxable supplies exceed $30,000, either in a single calendar quarter or over the four preceding calendar quarters. Below that threshold you are a small supplier and registration stays optional. Enter your figures below for a clear answer.
- Total over 4 quarters
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- Highest single quarter
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- Room left before the threshold
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Enter your amounts to get an answer.
As long as your taxable supplies stay at or below $30,000 over four consecutive calendar quarters, you remain a small supplier and you are not required to collect GST or QST. You may still register voluntarily: you would then have to collect the taxes, but you could recover the taxes you pay on your purchases (ITCs and ITRs).
You stop being a small supplier because your last four calendar quarters add up to more than $30,000. You must register for the GST and QST files and start collecting the taxes on your taxable supplies. In return, you can claim ITCs and ITRs on your business purchases.
A single calendar quarter goes over $30,000 on its own. In that case you lose small-supplier status as of the supply that crosses the threshold — not at the end of the quarter. You have 30 days to register, and you must collect the taxes on that supply.
This tool is provided for information purposes only. Some situations (taxi, commercial ride-sharing, non-residents) follow special rules.
Frequently asked questions
What is the GST/QST registration threshold?
The threshold is $30,000 of taxable supplies. You stop being a small supplier as soon as that amount is exceeded, either in a single calendar quarter or over the four preceding calendar quarters.
If I hit exactly $30,000, do I have to register?
No. The rule is about exceeding the threshold, not reaching it. At exactly $30,000 you remain a small supplier. The obligation kicks in at the first dollar above it.
How long do I have to register after going over the threshold?
You have 30 days from the first supply made other than as a small supplier. Note that you must collect the taxes on that supply even if your registration is not yet complete.
Is it worth registering voluntarily?
Often yes, if your customers are registrants themselves or if you have significant expenses. Registration entitles you to input tax credits (ITCs) and input tax refunds (ITRs) on your business purchases. In exchange, you have to file returns on a regular basis.
Which sales count towards the calculation?
Taxable supplies made worldwide, by you and by your associates, including zero-rated supplies. Exempt supplies are not included. Use pre-tax amounts. If you are unsure about a specific category, confirm with Revenu Québec.
How the $30,000 threshold actually works
The threshold is rolling. It does not reset on January 1: you always look at the last four calendar quarters, whatever month you are in.
Calendar quarters are fixed:
| Quarter | Period |
|---|---|
| Q1 | January 1 – March 31 |
| Q2 | April 1 – June 30 |
| Q3 | July 1 – September 30 |
| Q4 | October 1 – December 31 |
Two rules coexist, and they do not have the same consequences:
The four-quarter rule. If your taxable supplies over the four preceding calendar quarters add up to more than $30,000, you stop being a small supplier. This is the common case: steady growth that eventually crosses the line.
The single-quarter rule. If one quarter exceeds $30,000 on its own, you lose the status immediately, as of the supply that crosses the threshold — not at the end of the quarter. You must collect the taxes on that supply. This is the situation of one large contract landing at once.
At exactly $30,000 you remain a small supplier: the rule is about exceeding the threshold, not reaching it.
Which sales count?
The calculation includes taxable supplies made worldwide, by you and by your associates, including zero-rated supplies (taxed at 0%).
It does not include exempt supplies. The distinction between zero-rated and exempt is subtle but it changes the result: a zero-rated activity counts towards the threshold, an exempt one does not.
Use pre-tax amounts. If you are already charging taxes by mistake or out of caution, it is the amount excluding taxes that counts.
How long do I have to register?
You have 30 days from the first supply made other than as a small supplier.
Here is the trap: the obligation to collect the taxes starts before your registration is complete. If you invoice without taxes while waiting for your number, you will still owe Revenu Québec the taxes that should have been collected — and going back to a client to ask for another 14.975% is an awkward conversation.
The right reflex: as soon as you know the threshold will be crossed, start the registration and tell your clients.
Should I register voluntarily before the threshold?
Voluntary registration is available below the threshold and it is often worthwhile.
In favour: you can claim input tax credits (ITCs) and input tax refunds (ITRs) on your business purchases. If you are investing in equipment, software or subcontracting, that is 14.975% recovered on those expenses. Charging taxes also makes you look like an established business to corporate clients.
Against: you have to file returns on a schedule, keep your records accordingly, and your prices become 14.975% higher for individual customers, who recover nothing.
Rule of thumb: if your clients are mostly registered businesses, voluntary registration costs you nothing commercially and earns you the ITCs/ITRs. If your clients are individuals, wait for the threshold.
Special cases
Some activities must register from the first sale, regardless of the $30,000 threshold — notably operating a taxi and commercial passenger transportation. Separate rules also apply to non-residents selling in Quebec.
If your situation falls into one of those categories, this calculator does not apply: check directly with Revenu Québec.
What happens once you are registered?
You must collect GST (5%) and QST (9.975%) on your taxable supplies, show them on every invoice along with your registration numbers, and file returns at the frequency assigned to you.
Our GST/QST sales tax calculator breaks down each line to invoice, and the reverse sales tax calculator does the opposite from a tax-included amount.