1. What is GST/QST?

GST (Goods and Services Tax) and QST (Quebec Sales Tax) are consumption taxes applied to most goods and services in Canada (GST nationwide, QST in Quebec). As of 2025, the rates are 5% for GST and 9.975% for QST.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• Pre-tax Amount — The amount before taxes
• 1.05 — Represents 5% GST
• 1.09975 — Represents 9.975% QST (applied after GST)

Explanation: QST is calculated on the amount after GST has been added, which is why the rates are multiplied sequentially.

3. Importance of Tax Calculation

Details: Accurate tax calculation is crucial for businesses and consumers in Quebec to understand the true cost of purchases and ensure proper accounting.

4. Using the Calculator

Tips: Enter the pre-tax amount in Canadian dollars. The calculator will show the GST, QST, and total amount including both taxes.

5. Frequently Asked Questions (FAQ)

Q1: Why is QST calculated after GST?
A: In Quebec, QST is applied to the price after GST has been added, making it a tax on a tax.

Q2: Are there exemptions to these taxes?
A: Yes, certain items like basic groceries, prescription drugs, and exports may be exempt or zero-rated.

Q3: How often do these tax rates change?
A: Tax rates are set by government and can change, though changes are infrequent. This calculator uses 2025 rates.

Q4: Do I need to pay both taxes if I'm not in Quebec?
A: No, QST only applies in Quebec. Other provinces may have different provincial sales taxes.

Q5: How should businesses handle these taxes?
A: Businesses must register, collect, and remit these taxes to the government according to specific rules and schedules.