How do I calculate the $30,000 threshold for GST and QST?

You’re approaching the well-known $30,000 sales threshold and, suddenly, a question that seemed simple no longer is.

Is it $30,000 profit? Per year? Before or after expenses? And if a big bill makes you exceed the threshold at once, do you have to tax just what goes beyond?

The short answer: the calculation usually includes your taxable supplies, before expenses and without taxes. You have to check your sales by calendar quarter, then apply two different rules depending on the speed at which you exceed $30,000.

Let’s break it down simply.

What exactly counts toward the $30,000?

This is not your profit. Do not subtract your computer, fuel, software, or other expenses before calculating the threshold.

Instead, start with revenue from taxable supplies, including supplies that are zero-rated at 0%. The calculation is made before expenses but excludes the GST, HST, and QST collected.

Here is the general picture:

The distinction between “zero-rated” and “exempt” is important. A zero-rated supply is taxable at 0%, so it counts toward the threshold. An exempt supply is not taxable, so it normally does not count toward this calculation.

A sale to a U.S. customer does not automatically disappear from the calculation. Some supplies destined for foreign countries are zero-rated, but zero-rated supplies still count. If sales outside Quebec or Canada represent a large share of your revenue, confirm how they should be treated.

If you are self-employed and operate two activities under your own name, you do not receive two separate $30,000 thresholds. If you earn $18,000 from consulting and $14,000 from an online store, for example, the taxable revenue from both activities usually must be combined. The rule may also include supplies from associated persons, a more technical concept to verify if you control multiple businesses.

The full official criteria are available on Revenu Québec’s Small supplier page.

Do not calculate only from January 1 to December 31

Looking only at annual sales is convenient, but not precise enough to make a decision.

The calculation uses calendar quarters:

• 1 January to 31 March;
• 1 April to 30 June;
• 1 July to 30 September;
• 1 October to 31 December.

At the end of each quarter, review the total for that quarter and the previous three calendar quarters. The calculation can therefore span New Year’s Day. It is neither your fiscal year nor a rolling 365-day period.

At exactly $30,000, you have not yet crossed the threshold. The rules change once you exceed $30,000.

There are two ways to exceed the threshold

This distinction matters because when you must begin collecting taxes depends on how you crossed the threshold.

Case 1: You’re over $30,000 in a single quarter

Suppose you made $28,500 in taxable sales between July 1 and September 11. On September 12, you make a $3,000 sale.

Your total for the quarter is $31,500. You immediately cease to be a small supplier. The sale of $3,000 that makes you exceed the threshold is taxable in full, not just $1,500 above the limit. The following taxable sales are also taxable.

In this example, your registration must take effect on September 12, and you have 29 days from that date to register.

One large invoice can change your situation immediately, even if sales in previous quarters were modest.

Case 2: You exceed $30,000 by adding several quarters

Consider these sales instead:

You exceeded the threshold across four consecutive calendar quarters but never during a single quarter. You remain a small supplier until the end of the month following the quarter in which you exceeded it.

In this example, the quarter ends on September 30. You cease to be a small supplier on October 31. If your next sale is on November 2, your registration must take effect no later than that date, and you begin charging taxes on that sale. You have 29 days from November 2 to register.

This second scenario has a different timeline. That is why the simple phrase “start charging taxes as soon as you reach $30,000” can be misleading.

The Canada Revenue Agency presents both scenarios with dated examples . It is an excellent reference for checking your own timeline.

A simple way to follow your threshold

You do not need a NASA-worthy accounting file. Keep a before-tax total for each of the four calendar quarters. Each time you update your numbers, check two things: the current quarter total and the total of the last four consecutive calendar quarters.

As you approach $30,000, review each invoice instead of checking only once a year. An accepted proposal is not necessarily a sale that must be included immediately, but it helps you anticipate what is coming. If you will invoice an $8,000 project next week, determine how it affects your status before clicking Send.

Keep notes explaining what you included or excluded. Your future self, or your accountant, will appreciate not having to reconstruct the reasoning six months later.

You’re approaching the threshold: what to do now?

Start by confirming your total and the likely date you will exceed the threshold. Then prepare your registration with Revenu Québec. In Quebec, Revenu Québec generally administers the GST/HST and QST, and its page on GST and QST registration explains the process.

Consider the practical details too. Will your prices be displayed before tax? Do your contracts mention taxes? Is your invoicing tool ready? If you use Parle, you can enter your tax numbers in the invoicing settings . Once your registration date is established, Parle can apply the appropriate Canadian taxes and prepare a tax report. The software simplifies invoicing, but it does not determine your tax status.

Our article about tax management for a Quebec online store explains this in more detail. If you primarily bill for services, the Invoicing module page also shows what clients see and how taxes are compiled.

Should you register voluntarily before $30,000?

You can generally choose to register while still considered a small supplier. This may be worthwhile if you have significant taxable business expenses because you could then claim input tax credits and refunds . In return, you must collect taxes, file returns, and remain registered for at least one year.

The right choice depends heavily on your customers, prices, and expenses. A business selling mainly to other registered businesses faces a different commercial impact than one selling directly to consumers. Do the math before volunteering for more paperwork. There is already enough of it.

A few cases where it’s worth validating

The general rule covers many self-employed and small businesses, but not all situations. Taxis and commercial carpooling may have to register regardless of the threshold. There are also specific QST obligations for certain tobacco vendors, new tires and road vehicles.

Exempt sales, structures involving multiple companies, associated persons, and supplies made outside Quebec may also require a more detailed analysis.

If in doubt, call Revenu Québec or confirm with your accountant. Have your sales separated by quarter and a clear description of what you sell. You will get a much more useful answer than with a vague “I made about $30,000 this year.”

The key point to remember

The $30,000 threshold applies to relevant taxable supplies before expenses, not to profit. It is measured using calendar quarters, not simply once a year. If you exceed the threshold in one quarter, the entire sale that puts you over becomes taxable. If you exceed it gradually across several quarters, you generally cease to be a small supplier at the end of the month following the quarter when you went over.

The calculation is not so intimidating once the sales are in the right categories and you are using the right calendar.

This article presents the general rule and does not replace tax advice tailored to your situation.