Quebec Tax Calculator: GST QST3.1.3 - Google Play

Type a price and instantly see GST (5%), QST (9.975%) and the total — with every step of the math laid out so you can check it yourself.

Most calculators hide what they do with a discount. This one applies the discount first, shows the taxable subtotal, and computes taxes on that amount, exactly like the receipt will.

WHAT YOU GET
• GST and QST for Quebec at the current rates
• Reverse calculation: type the total, get the price before tax
• Discount applied before tax, with the taxable subtotal shown
• Tip on the base you choose: pre-tax subtotal, before discount, or after tax
• Split the bill between any number of people
• A simple view by default — tip, discount and split are one tap away
• Built-in calculator and a shopping list
• English and French, with Canadian currency formatting
• Light and dark mode
• Works offline, no account, no sign-up

HOW THE MATH WORKS
Original amount → discount → taxable subtotal → GST and QST on the subtotal → total after tax → tip → amount to be paid → per person. Every line is rounded to the cent before the next step, so what you see always adds up.

OFFICIAL SOURCES
Tax rates come from the official government pages, linked directly in the app:
• GST (Government of Canada): https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/charge-collect-which-rate/calculator.html
• QST (Revenu Québec): https://www.revenuquebec.ca/en/businesses/consumption-taxes/gsthst-and-qst/basic-rules-for-applying-the-gsthst-and-qst/

This app is not affiliated with or endorsed by any government body. Results are estimates for personal use.