GST/QST for self-employed workers in Quebec: registration thresholds, timing, and common errors

Most new self-employed workers in Quebec hear about the $30,000 threshold for GST/QST without really knowing what it covers or when they must register. Some register too late; others charge tax when they do not have to.

This 2025 guide summarizes the main points in plain language.

1. Small supplier vs mandatory registration

In general, you are a small supplier if:

• Your worldwide taxable revenues (before tax) do not exceed $30,000 over four consecutive calendar quarters.

In that case:

• Registration for GST/QST is not mandatory.
• You may choose to register voluntarily if it is beneficial.

Once you exceed the threshold:

• You must register and start charging GST/QST on taxable sales.

2. Simple threshold example

Imagine a consultant in Quebec:

• 2025 Q1: $7,000 in sales.
• 2025 Q2: $8,000.
• 2025 Q3: $9,000.
• 2025 Q4: $10,000.

Total over four rolling quarters: $34,000.

You cross the $30,000 mark during the year. You normally become required to register for GST/QST as of a specific date, usually when you exceed the threshold. At that point you must:

• Register for GST/QST.
• Start charging tax on taxable sales.
• File returns and remit the collected amounts.

3. When it makes sense to register earlier

Sometimes registering before you hit $30,000 is smart:

• You incur lots of taxable expenses (equipment, software, subcontractors).
• Most of your clients are businesses that recover GST/QST.

By registering earlier, you can claim input tax credits/refunds on eligible expenses.

4. Common mistakes to avoid

• Confusing revenue with profit: the $30,000 threshold is based on gross revenue, not net income after expenses.
• Ignoring out-of-province sales: some may still be taxable or count toward the threshold.
• Not updating contracts: once registered, you must clarify whether prices are "before tax" or "tax included".

For a broader discussion of expenses, see:

• Self-employed in Quebec: which business expenses can you really deduct in 2025?.

5. Obligations after registration

Once registered for GST/QST you must:

• Charge applicable taxes on taxable supplies.
• File returns at the assigned frequency (monthly, quarterly, or annually).
• Keep detailed records of sales and taxable expenses.

Missing deadlines can lead to:

• Interest and penalties.
• Estimated assessments if returns are not filed.

6. Keeping records under control

• Use a separate business bank account.
• Organize invoices and receipts by month and type (sales, expenses, capital assets).
• Track GST/QST paid on purchases so you can claim it back when allowed.

A good record-keeping system also makes your annual income tax returns (T1/TP1) easier.

Call to action

If you are self-employed in Quebec and unsure when to register for GST/QST or how to manage your returns, TaxCove can help you evaluate your numbers, confirm thresholds, and set up a simple tracking system. To get started, fill out the form on the secure tax intake form page.

Important notice

This article provides general information only and does not replace personalized tax advice. GST/QST rules have many nuances depending on your activity and where your clients are located. Always confirm with a professional or directly with Revenu Quebec and the CRA.