Reverse Sales Tax Calculator Quebec: GST QST Reverse Calculation

Need to find the original price before taxes? This reverse tax calculator is specially designed to perform the reverse GST QST calculation for Quebec residents. Enter the amount including taxes and reverse calculator will remove the GST and QST present in the total price.

Quebec Reverse Tax Calculator

Reverse GST QST calculation for Quebec residents in 2025

Enter the total amount (taxes included) to automatically calculate the base amount and the GST/QST tax breakdown.

Tax Breakdown

Amount before taxes $0.00
GST (5%) $0.00
QST (9.975%) $0.00
Total taxes (GST + QST) $0.00
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How to use the reverse tax calculator?

  • To calculate the amount before taxes, simply enter the amount including all taxes in the field provided.
  • The reverse GST and QST calculator will automatically perform the calculation and display all taxes applied as well as the price before taxes in Quebec.
  • The calculator will display the GST, QST, the total GST + QST, and the total amount excluding taxes. This excluding tax/including tax converter is advanced and up-to-date according to Quebec tax regulations.

What are GST and QST, and to calculate reverse taxes manually?

The GST (Goods and Services Tax) and the QST (Quebec Sales Tax) are the two main consumption taxes applied to the majority of goods and services sold in Quebec. The Goods and Services Tax (GST) is a 5% federal value-added tax on most services, sales, goods, and other items imported or consumed in Canada. The QST is a 9.975% provincial value-added tax specific to Quebec.

Reverse tax calculations determine the pre-tax selling price from an amount that already includes GST and QST. This is done using a formula or an automated calculator that extracts the GST, QST, and pre-tax amounts from the total including tax.

To find the general formula for calculating reverse taxes , as we know, the combined tax rate in Quebec is:

  • GST = 5%
  • QST = 9.975%

Thus, the total effective tax multiplier is:
Total multiplier = (1 + TPS) × (1 + TVQ) = (1+0.5) × (1+0.09975) = 1.1547375

Amount without taxes = Amount with taxes / 1.1547375

For example, the price including taxes is $150, now to find the price before taxes, we have:

Amount without taxes = 150 / 1.1547375 = $130

To calculate taxes separately:

GST = 150 × 0.5 = $7.5

QST = 150 × 0.09957 = $14.96

Reverse Tax Calculator helps you accurately calculate GST, QST, and pre-tax prices. It’s a tax converter that converts after-tax prices to pre-tax prices.