GST and QST Calculator (Quebec Sales Tax)

GST is 5% and QST is 9.975%. Together they add 14.975% to the pre-tax price. An item priced at $100 therefore costs $114.98 at the register: $5.00 of GST and $9.98 of QST ($9.975 rounded up to the next cent).

Since January 1, 2013, QST has been calculated on the selling price excluding GST. In other words, there is no longer a “tax on tax”: both rates apply to the same starting amount. That is why the QST rate is 9.975%, a figure set so the overall burden stayed equivalent to the previous method.

To add the taxes, multiply the pre-tax price by 5% to get the GST, then multiply the same price by 9.975% to get the QST. Each tax is rounded to the cent: according to Revenu Québec, a fraction of 0.5 cent or more is rounded up to the next cent and a smaller fraction is dropped. Finally, add the price, the GST and the QST.

Example: a $250 service gives $12.50 of GST and $24.94 of QST ($24.9375 rounded), for a total of $287.44. Multiplying directly by 1.14975 almost always gives the same result, but rounding each tax separately is the method to use on an invoice, where each tax is shown on its own line.

If you only have the tax-included total, divide it by 1.14975 to find the pre-tax price. A common mistake is to subtract 14.975% from the total: that gives an amount that is too low, because the taxes were calculated on the pre-tax price, not on the total.

Example: a $50 receipt corresponds to about $43.49 before taxes, including $2.17 of GST and $4.34 of QST. The calculator adjusts the last cent so that the price, GST and QST add up exactly to the total you entered.

Most goods and services are taxable at 5% and 9.975%. Some are zero-rated, meaning taxable at 0%: this includes most basic groceries, prescription drugs and certain medical devices. Others are exempt, such as long-term residential rent, most health care and financial services, and child care services.

The detailed rules are numerous (the same food item can be zero-rated at the grocery store and taxable in a restaurant, for example). When in doubt, check with Revenu Québec or a professional before invoicing.

A tip left voluntarily at a restaurant is not part of the taxable price: GST and QST are calculated on the bill first, then the tip is added. Mandatory service charges added by the establishment, however, are part of the price and are generally taxable.

A discount given by the seller at the time of sale reduces the amount on which taxes are calculated. When checking a receipt with several items, the rounding rule also allows taxes to be calculated on the total of the taxable items rather than item by item, which sometimes explains a one-cent difference from a calculation done by hand.

A business generally has to register for GST and QST once its taxable sales exceed $30,000 over four consecutive calendar quarters; below that, it is a small supplier and registration is optional. In Quebec, Revenu Québec administers the QST and, for most businesses, the GST as well.

Once registered, a business collects the taxes from its customers and remits them, but it can also recover the taxes paid on its business purchases through input tax credits (ITCs) for GST and input tax refunds (ITRs) for QST. Registration numbers must appear on invoices when the rules require it.

This calculator is for amounts sold or bought in Quebec. Elsewhere in Canada other rates apply: GST only in some provinces and territories, and harmonized sales tax (HST) or a separate provincial sales tax in others.