GST QST Calculator - Quebec Tax Split

A GST QST calculator adds or removes Quebec sales taxes by splitting the federal Goods and Services Tax and the Quebec Sales Tax into separate amounts. Use it when preparing a taxable Quebec invoice, checking a supplier total, separating taxes for bookkeeping, estimating a mixed invoice with exempt lines, or explaining why Quebec tax is not the same as a single HST rate.

• • Add tax to a quote: Start with the tax-exclusive price and calculate GST, QST, total tax, and the customer total.
• • Remove tax from a receipt: Start with a tax-included total and recover the taxable subtotal and separate tax amounts.
• • Handle mixed invoices: Use taxable share when only part of the sale is subject to regular Quebec sales taxes.
• • Check invoice lines: Compare the GST and QST split against an invoice before posting it to accounting records.

Quebec commonly shows two sales-tax lines instead of one combined HST line. The calculator keeps those amounts separate because a buyer, seller, or bookkeeper may need the GST and QST values independently for review and reporting.

This tool handles straightforward arithmetic for taxable Quebec supplies. It does not decide whether a sale is taxable, zero-rated, exempt, made in Quebec, or subject to a special rule. Treat the result as an invoice math check, then confirm the tax treatment when the transaction is unusual.

For Australian GST rather than Quebec GST and QST, use the GST calculator with the Australian 10% GST workflow.

The standard Quebec calculation applies both rates to the selling price before taxes, then adds the two tax amounts to the invoice total.

• Entered amount: The tax-exclusive subtotal in add mode or the tax-included total in remove mode.
• Taxable share: The percentage of the amount that should receive the regular GST and QST rates.
• GST rate: The federal GST rate used for taxable Quebec supplies, defaulted to 5%.
• QST rate: The Quebec sales tax rate used for taxable Quebec supplies, defaulted to 9.975%.

For a fully taxable $100 sale, GST is $5.00 and QST is $9.98 before display rounding, so total tax is $14.98 and the invoice total is $114.98. The exact combined rate is 14.975%, but invoices usually display currency amounts to cents.

To remove tax from a fully taxable total, divide the total by 1.14975. A $114.975 tax-included amount therefore backs into a $100 taxable subtotal, $5 GST, and $9.975 QST before currency rounding.

According to Revenu Québec, GST is calculated at 5% on the selling price and QST at 9.975% on the selling price excluding GST.

For a single custom sales-tax rate without a separate Quebec split, the sales tax calculator gives a simpler add-or-remove workflow.

These terms explain what the calculator is doing and where judgment is still required.

The taxable share field is for practical invoice checks, not for classifying supplies. For example, if half of a quote is taxable services and half is exempt rent, set taxable share to 50% only after you know that treatment is correct.

Rounding can create one-cent differences between systems. Some invoices round each line, while others calculate tax on grouped taxable subtotals. When matching a real invoice, use the same line grouping and rounding method as the source document.

If you are comparing Quebec taxes with value-added tax pricing, the VAT calculator keeps VAT-inclusive and VAT-exclusive amounts separate.

Use the GST QST calculator with the same method as the invoice or receipt you are checking so the taxable base is interpreted correctly.

1. 1 Choose add or remove: Use add mode for a pre-tax price and remove mode for a total that already includes Quebec taxes.
2. 2 Enter the amount: Use the subtotal, quote, receipt total, or invoice total depending on the selected mode.
3. 3 Set taxable share: Leave it at 100% for a fully taxable sale, or lower it when only part of the amount is taxable.
4. 4 Review the rates: Keep 5% GST and 9.975% QST for regular Quebec taxable supplies unless you are testing a separate assumption.
5. 5 Read the split: Use taxable subtotal, GST, QST, total tax, and invoice total to compare against the document.

If a consultant sends a $1,000 taxable Quebec quote before tax, add mode returns $50 GST, $99.75 QST, $149.75 total tax, and a $1,149.75 invoice total. If a receipt already shows $1,149.75 as the total, remove mode recovers the same $1,000 taxable subtotal and the same two tax amounts.

For income-tax planning beyond sales-tax invoice math, the Canada tax calculator estimates broader Canadian tax outcomes.

Separate GST and QST outputs make routine invoice checks faster and reduce posting errors.

• • Invoice review: Check whether the tax split matches the taxable subtotal before sending or paying an invoice.
• • Bookkeeping support: Post GST and QST to separate accounts instead of relying on a single combined tax number.
• • Receipt cleanup: Back out the pre-tax amount from a receipt total when the subtotal is missing or unclear.
• • Quote preparation: Show a customer the subtotal, each tax, and the final amount before approval.
• • Mixed-line estimates: Model partial taxable invoices before building the final line-by-line invoice in accounting software.

For business records, the tax split matters more than the combined rate. A customer may want to know the total, but the seller usually needs separate GST and QST amounts for tax accounts, remittance review, and reconciliation.

The GST QST calculator can also help catch a common Quebec mistake: applying QST to the GST-included price. Current ordinary arithmetic uses the selling price excluding GST as the QST base, so both tax lines start from the same taxable subtotal.

For U.S. purchases where state-level rates matter, the state sales tax calculator covers state sales-tax estimates instead of Quebec GST and QST.

The arithmetic is direct, but tax treatment depends on the transaction. Confirm the source facts before relying on the result.

• • This calculator does not determine whether you must register, collect, remit, or claim input tax credits or refunds.
• • It does not replace Revenu Québec guidance for exempt, zero-rated, imported, interprovincial, or special-sector transactions.
• • For mixed invoices, a line-by-line calculation is more reliable than estimating with a taxable-share percentage.

If the sale crosses provincial or national borders, do not assume Quebec rates apply. The place-of-supply rule can change the tax result, and some supplies that look similar on an invoice can have different tax treatment.

Use the custom rate fields only for audit, historical, or scenario checks. For current regular Quebec taxable supplies, keep the GST QST calculator defaults at 5% GST and 9.975% QST unless an official source says otherwise for the transaction.

According to Revenu Québec invoice guidance, invoice information requirements depend on invoice amount and include GST or QST details for larger taxable invoices.

According to Canada Revenue Agency, the rate of GST/HST to charge depends on the place of supply, and zero-rated supplies have a 0% GST/HST rate throughout Canada.

When comparing shopping costs across U.S. states, the USA sales tax comparison calculator is more relevant than a Quebec-only tax split.