What does the 14.975% combined reference mean?

It is the effective single multiplier you get when 5% GST pairs with 9.975% QST calculated on the price excluding GST. Multiplying the pre-tax base by 1.14975 lands on the same tax-inclusive total as applying the two-step stack for that common scenario.

Is TVQ different from QST?

TVQ is the French label for Quebec sales tax. English materials usually say QST. Both refer to the provincial part that sits alongside GST.

When do I need to split GST and QST instead of one combined rate?

Accounting systems sometimes need separate federal and provincial amounts, or a line may not follow the standard stack. After you isolate the pre-tax base with the combined reference, use Revenu Québec rules or your finance workflow to break the tax into GST and QST components.

Where should I enter numbers for a quick check?

Use the CalcLook Quebec reverse tax calculator when you want CAD outputs with the combined reference rate prefilled.

Are all Québec sales subject to GST and QST?

Revenu Québec groups supplies as taxable, zero-rated, or exempt. Only the treatment that applies to your transaction determines whether GST and QST are collected and at what effective rate, so mixed carts should be split by line before you reuse one combined divisor on the entire ticket.

When would a Québec business charge HST instead of GST plus QST?

According to Revenu Québec collecting guidance, GST and QST registrants in Québec may need to charge HST on taxable sales tied to participating HST provinces. The province list and conditions can change, so confirm the current wording on Revenu Québec and use the tax lines on the invoice for your reverse calculation.

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How to Reverse GST and QST

Quebec GST and QST backwards using the usual combined reference, TVQ versus QST, supply types on Revenu Québec, and why cross-province invoices may show HST. Links to official pages plus the Quebec reverse tax calculator; educational reference only.

Start with the right total

This page walks through the math only; it is not guidance from Revenu Québec. For supply types, registration, and collection rules, follow the linked government pages.

Confirm you are working from a Quebec total that already includes both federal GST and provincial QST for the goods or services in question. If the receipt shows separate lines, add the taxed components before you run one reverse pass.

Divide by 1.14975 (the usual shortcut)

For the common stack summarized as 14.975%, convert the percent to 0.14975, add one, and divide the inclusive total by 1.14975. That yields the estimated pre-tax base; subtract it from the total to see the combined GST and QST portion for that reference model. This combined shortcut matches the usual two-step stack described by Revenu Québec; if your line is not a standard taxable supply, pause and read the official rules before using the shortcut.

Keep the two-step story in mind

Official stacking applies 5% GST to the net price, then 9.975% QST on the amount excluding GST. The combined shortcut matches how many receipts show one tax-included total without showing every intermediate penny.

Taxable, zero-rated, and exempt supplies

Revenu Québec groups supplies into taxable, zero-rated, and exempt categories. That controls whether GST and QST apply to your line and how credits work. Before you rely on the 14.975% shortcut, confirm each line is a standard taxable supply in Québec. For exceptions and edge cases, read Types of supplies on Revenu Québec instead of relying on this short page alone.

Selling in other provinces (when HST shows up)

The rules for charging tax are different from the rules for reading a receipt. Revenu Québec publishes guidance for businesses that must collect GST and QST in Québec and may need to charge HST on taxable sales tied to other provinces. If you are checking a personal receipt, follow the tax lines printed on the bill instead of assuming Quebec's combined rate applies. Read the full explanation on Collecting GST and QST instead of relying on this short page alone.

Contrast with Ontario HST

Ontario typically bills 13% HST as one harmonized rate. The reverse mechanics still use division by 1 + r, but the rate differs. See how to calculate HST backwards when the province is Ontario rather than Quebec.

Related CalcLook pages and official rules

Quebec reverse tax calculator
Canada reverse tax guide
Reverse tax formula reference
Revenu Québec — basic GST/HST and QST rules (QST is calculated on the amount before GST is added).
Revenu Québec — types of supplies.
Revenu Québec — collecting GST and QST.

FAQ

What does the 14.975% combined reference mean?: It is the effective single multiplier you get when 5% GST pairs with 9.975% QST calculated on the price excluding GST. Multiplying the pre-tax base by 1.14975 lands on the same tax-inclusive total as applying the two-step stack for that common scenario.
Is TVQ different from QST?: TVQ is the French label for Quebec sales tax. English materials usually say QST. Both refer to the provincial part that sits alongside GST.
When do I need to split GST and QST instead of one combined rate?: Accounting systems sometimes need separate federal and provincial amounts, or a line may not follow the standard stack. After you isolate the pre-tax base with the combined reference, use Revenu Québec rules or your finance workflow to break the tax into GST and QST components.
Where should I enter numbers for a quick check?: Use the CalcLook Quebec reverse tax calculator when you want CAD outputs with the combined reference rate prefilled.
Are all Québec sales subject to GST and QST?: Revenu Québec groups supplies as taxable, zero-rated, or exempt. Only the treatment that applies to your transaction determines whether GST and QST are collected and at what effective rate, so mixed carts should be split by line before you reuse one combined divisor on the entire ticket.
When would a Québec business charge HST instead of GST plus QST?: According to Revenu Québec collecting guidance, GST and QST registrants in Québec may need to charge HST on taxable sales tied to participating HST provinces. The province list and conditions can change, so confirm the current wording on Revenu Québec and use the tax lines on the invoice for your reverse calculation.