How to Use Canada GST/QST Calculator
The Canada GST/QST Calculator is built for Quebec shoppers, freelancers, and business owners who need a quick tax estimate.
- Pick a Mode — Choose to calculate from a pre-tax amount or back out the pre-tax amount from a total that already includes GST and QST.
- Enter the Amount — Type the pre-tax price or the after-tax total, depending on the mode you picked.
- Confirm or Adjust Rates — The Canada GST/QST Calculator defaults to GST 5% and QST 9.975%, which you can override for special goods or future rate changes.
- Pick a Currency — Use the currency selector so all amounts display the right symbol (CAD-style values render with your chosen prefix).
- Read the Result — The Canada GST/QST Calculator shows pre-tax amount, GST, QST, total tax, and after-tax total at a glance.
Formula & Theory - Canada GST/QST Calculator
The Canada GST/QST Calculator uses these standard Quebec tax formulas:
GST = Pre-tax amount × 5%
QST = Pre-tax amount × 9.975%
Total Tax = GST + QST
After-tax Total = Pre-tax amount + GST + QST
Reverse: Pre-tax amount = After-tax total ÷ 1.14975| Symbol | Meaning |
|---|---|
| GST | Goods and Services Tax (federal) |
| QST | Quebec Sales Tax (provincial) |
| Pre-tax amount | Price before any tax is added |
| After-tax total | Final price the buyer pays |
Assumptions and Limits
The Canada GST/QST Calculator assumes the supplied rates are correct and ignores rebates, input tax credits, and rounding rules used by certain registered businesses. For accounting or filing, always confirm with Revenu Quebec and the CRA.
Use Cases for Canada GST/QST Calculator
The Canada GST/QST Calculator is useful for many everyday and business scenarios:
- Retail and ecommerce pricing — Show shoppers in Quebec the all-in price before checkout.
- Freelance invoicing — Add the right GST/QST to client invoices and verify totals.
- Expense tracking — Reconcile a receipt that only shows the after-tax total.
- Budget planning — Estimate how much of a planned purchase will be tax.
Because everything runs in your browser, you can switch between modes and rates instantly and compare scenarios without spreadsheets.