GST + QST Calculator — Quebec Sales Tax
Add or remove Canadian federal GST and Quebec provincial QST in one step. The default rates reflect the current 2025 values — edit them if rates change or you need a different scenario.
Mode
%
%
Price including both federal GST and Quebec QST
114.98
TotalPre-tax
87%
GST
4.3%
QST
8.7%
- 1
GST amount
100 × 5% = 5 - 2
QST amount
100 × 9.975% = 9.98 - 3
Total with GST + QST
100 + 5 + 9.98 = 114.98
How does this calculator work?
In Quebec, both federal GST (5%) and provincial QST (9.975%) are calculated on the pre-tax price. Combined rate = 14.975%: a $100 item becomes $114.98. To reverse, divide the total by 1.14975. Both rates are editable for future changes or other provinces.
Formula
How this is calculated
Canada levies a federal Goods and Services Tax (GST) at 5% and Quebec additionally levies its own Quebec Sales Tax (QST, or TVQ in French) at 9.975%, for a combined rate of 14.975% in Quebec. Since a 2013 harmonisation, both taxes are calculated on the same pre-tax base — QST is no longer calculated on the GST-inclusive price as it was before 2013. The combined formula is straightforward: Total = pre-tax × (1 + GST + QST), or Total = pre-tax × 1.14975 at the current 2025 rates.
In "add" mode the amount entered is the pre-tax (before-tax) figure and the calculator multiplies by each rate to find the GST and QST amounts, then adds them to give the total. In "remove" mode the amount is the tax-inclusive total; the pre-tax base is recovered by dividing by (1 + GST + QST), and the tax amounts are the difference. Removing tax is not the same as subtracting 14.975% of the total — because the tax was applied on top of a smaller base, division by 1.14975 is the correct reversal.
Both rates are editable so the calculator remains useful if rates change. The GST rate has been 5% since January 2008 (reduced from 6% and then 7%); the QST rate has been 9.975% since January 2013.
Frequently asked questions
At the 2025 rates: 5% GST + 9.975% QST = 14.975% combined effective tax rate on the pre-tax price. A $100 item costs $114.98 after tax (rounded to the nearest cent).
Divide the total by 1.14975 to get the pre-tax base. The difference is the combined tax. Do not subtract 14.975% of the total — that gives a wrong result because the tax was applied to the smaller pre-tax base, not the larger total.
Since January 2013, both taxes are applied independently to the same pre-tax amount. Before 2013, Quebec applied QST on the GST-inclusive price, making the effective QST rate about 10.47% instead of 9.975%. The calculator uses the current (post-2013) method.
Also known as
TG we-Calculate Editorial Team. (2026). GST + QST Calculator — Quebec Sales Tax [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/gst-qst-calculator
TG we-Calculate Editorial Team. "GST + QST Calculator — Quebec Sales Tax." TG we-Calculate. 2026. https://we-calculate.com/calculator/gst-qst-calculator.
TG we-Calculate Editorial Team, "GST + QST Calculator — Quebec Sales Tax," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/gst-qst-calculator
@misc{wecalculate_gst_qst_calculator, title = {GST + QST Calculator — Quebec Sales Tax}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/gst-qst-calculator}}, year = {2026}, note = {TG we-Calculate} }
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