GST QST Calculator
In Quebec, you charge 5% GST and 9.975% QST on the same price before tax, and round each tax to the cent. On $100.00 the GST is $5.00, the QST is $9.98 and the total is $114.98. To find the amount before tax from a total, divide by 1.14975.
At a glance
- Rates: GST 5%, QST 9.975%, both on the price before tax (rates verified on October 30, 2026 on Revenu Québec’s site).
- Both directions: from the amount before tax to the total, or from a total with tax included back to the amount before tax.
- Private: it runs in your browser. Nothing you type is sent or stored.
Quebec sales tax calculator
Choose what you know, then type the amount.
The calculator covers Quebec only (GST and QST). It assumes the sale is taxable under both taxes; some goods and services are zero-rated or exempt.
GST and QST formula, with a worked example
QST is not charged on the GST: both taxes are worked out on the same selling price before tax. Revenu Québec describes it this way for the two-step method: apply 5% GST to the selling price, then apply 9.975% QST to the same price.
GST = amount before tax × 0.05
QST = amount before tax × 0.09975
total = amount before tax + GST + QST
Rounding: each tax to the cent
Work out each tax separately and round it to the cent. Revenu Québec says only fractions of $0.005 or more are rounded up to the next cent. For several items on one invoice, you can work out the taxes on the total of the items before rounding.
The one-step method (14.975%)
Revenu Québec also allows a one-step method (French page), where the register applies a combined 14.975% rate to the selling price. Because that rounds once instead of twice, the total can differ by a cent. Example on $19.90: two steps, GST $0.995 → $1.00 and QST $1.985025 → $1.99, so $2.99 in tax; one step, 19.90 × 14.975% = $2.980025 → $2.98. This calculator uses the two-step method.
Example: a $49.99 invoice
- GST: 49.99 × 0.05 = $2.4995, rounded to $2.50.
- QST: 49.99 × 0.09975 = $4.9865, rounded to $4.99.
- Total: 49.99 + 2.50 + 4.99 = $57.48.
On $100.00 the exact QST is $9.975: the $0.005 fraction rounds it up to $9.98, and the total to $114.98.
Reverse GST QST: find the amount before tax
When you only know the total with tax included (a receipt, an all-in quote), divide it by 1.14975 (1 + 0.05 + 0.09975) and round to the cent.
amount before tax = total ÷ 1.14975
Example: $114.98 ÷ 1.14975 = 100.004…, so $100.00 before tax, $5.00 GST and $9.98 QST.
Because each tax is rounded on its own, some totals do not match any amount before tax to the cent. The calculator tells you when that happens and gives the closest amount.
GST and QST on common amounts
Each tax is rounded to the cent separately.
| Before tax | GST (5%) | QST (9.975%) | Total |
|---|---|---|---|
| $1.00 | $0.05 | $0.10 | $1.15 |
| $5.00 | $0.25 | $0.50 | $5.75 |
| $10.00 | $0.50 | $1.00 | $11.50 |
| $20.00 | $1.00 | $2.00 | $23.00 |
| $25.00 | $1.25 | $2.49 | $28.74 |
| $50.00 | $2.50 | $4.99 | $57.49 |
| $75.00 | $3.75 | $7.48 | $86.23 |
| $100.00 | $5.00 | $9.98 | $114.98 |
| $150.00 | $7.50 | $14.96 | $172.46 |
| $200.00 | $10.00 | $19.95 | $229.95 |
| $250.00 | $12.50 | $24.94 | $287.44 |
| $500.00 | $25.00 | $49.88 | $574.88 |
| $750.00 | $37.50 | $74.81 | $862.31 |
| $1,000.00 | $50.00 | $99.75 | $1,149.75 |
| $1,500.00 | $75.00 | $149.63 | $1,724.63 |
| $2,000.00 | $100.00 | $199.50 | $2,299.50 |
| $2,500.00 | $125.00 | $249.38 | $2,874.38 |
| $5,000.00 | $250.00 | $498.75 | $5,748.75 |
| $10,000.00 | $500.00 | $997.50 | $11,497.50 |
Who charges GST and QST?
Revenu Québec says you must register for the GST and QST if you carry on commercial activities in Quebec, unless you are a small supplier. In Quebec, you register for both taxes with Revenu Québec.
- The $30,000 threshold: you are a small supplier as long as your taxable supplies (with those of your associates) do not exceed $30,000 in a calendar quarter or over the four preceding calendar quarters.
- Voluntary registration: a small supplier can register below the threshold, for example to claim back the tax paid on business purchases.
- Exceptions: some activities must register whatever the sales (taxi operators, for example).
Once registered, you charge both taxes to your customers and remit them to Revenu Québec. Your accountant can confirm your situation.
Showing GST and QST on an invoice
Revenu Québec sets what an invoice must show based on its total, tax included. That information is what lets your business customers claim their input tax credits and refunds.
| Invoice total | What to show |
|---|---|
| Under $100 | Seller’s name, date, total amount. For QST, also the tax amount and a description of the goods or service. |
| $100 to $499.99 | All of the above, plus the GST and QST amounts and your GST and QST registration numbers. |
| $500 or more | All of the above, plus the buyer’s name, the payment terms and a description of each item or service. |
- Show both taxes. The clearest way is one GST line and one QST line. If you show a single tax amount, the invoice must say it includes GST and QST.
- Don’t print 14.975%. Revenu Québec says the rates 9.97%, 14.97% and 14.975% must not appear on the document confirming the sale.
- Unregistered small supplier: don’t charge tax and don’t print a number.
To make the invoice, try the free invoice generator: it takes two taxes, each worked out on the subtotal and rounded to the cent, and has a “Quebec (GST 5% + QST 9.975%)” button that fills them in. Or start from an editable template such as the Word invoice template or the Excel invoice template and add a GST line and a QST line.
Sources
Verified on October 30, 2026. Rates and rules can change: check with Revenu Québec for your situation.
- 5% and 9.975% rates, tax on the selling price, and rounding: Revenu Québec, Calcul des taxes (French page).
- Small suppliers, $30,000 threshold: Revenu Québec, Details Concerning Small Suppliers.
- Who must register: Revenu Québec, Registering for the GST and QST.
- Invoice information: Revenu Québec, Preparing Invoices.
- GST and HST rates elsewhere in Canada: Canada Revenue Agency, Which rate to charge.
Questions people ask
How do I calculate GST and QST?
What are the GST and QST rates in Quebec?
How do I find the amount before tax from a total?
Is QST charged on top of the GST?
How do you round GST and QST?
How much is the tax on $1,000 in Quebec?
Do I have to charge GST and QST?
Which tax numbers go on an invoice?
Can I show 14.975% on my invoice?
Does the calculator save what I type?
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