GST/HST Calculator Canada
Enter the pre-tax amount and applicable tax rate.
Important note
Selling goods or services? The tax flips from something you pay to something you collect. Once a business’s taxable revenues pass $30,000 over any four consecutive calendar quarters, CRA’s small-supplier exemption ends: you must register for a GST/HST number, charge the rate of the province where your customer is supplied — 13% in Ontario — and remit what you collect. Quebec runs separately: the 9.975% QST is administered by Revenu Québec, not CRA, so selling into Quebec can mean two registrations and two returns.
How this calculator works
This calculator answers two questions: how much sales tax is added to a price, and what the tax-inclusive total is. It uses the two formulas baked into the page's JavaScript: Tax amount = pre-tax amount × (rate ÷ 100), and Total = pre-tax amount × (1 + rate ÷ 100).
The rate is whatever you type, because Canadian sales tax is not one number. Ontario and the Atlantic provinces use a harmonized HST (13% in Ontario — 5% federal GST plus an 8% provincial portion); Alberta and the territories use 5% GST only; Manitoba and Saskatchewan combine 5% GST with provincial tax; Quebec pairs 5% GST with 9.975% QST. Enter the combined effective rate for your province and transaction, and the calculator does the rest.
One limit to know: it only computes tax forward from a pre-tax amount. If you already have a tax-inclusive price, divide it by (1 + rate ÷ 100) to work backwards — the worked example below shows exactly how.
Worked example
With the page's defaults — $100 at 13%, the Ontario HST rate — the tax is $100 × 13 ÷ 100 = $13.00 and the total is $100 × 1.13 = $113.00.
Try a real purchase: a $299.99 jacket bought in Alberta, where only 5% GST applies. Tax = $299.99 × 0.05 = $15.00 (rounded), and the total is $314.99. The same jacket in Ontario at 13% HST would carry $39.00 in tax for a $338.99 total — a $24 difference on the same sticker price, which is exactly why entering the right rate matters.
Going backwards: a $1,130 restaurant bill in Ontario includes 13% HST. Pre-tax price = $1,130 ÷ 1.13 = $1,000.00, so the tax buried in the bill is $130.00.
Practical tips
- Confirm the rate before you quote. Charging 13% HST to an Alberta customer (or 5% GST to an Ontario one) will either eat your margin or overcharge them — and the calculator cannot catch that mistake for you.
- Check that the item is taxable. Basic groceries and many medical services are zero-rated or exempt. This tool assumes the full rate applies, so verify taxability first.
- Freelancers: quote pre-tax and tax separately. It keeps invoices clean and makes it obvious you are collecting GST/HST to remit, not padding the price.
What rate should I enter for Ontario?
Enter 13 — the 2026 Ontario HST rate, which is also this page's default. That single number already combines the 5% federal GST and the 8% Ontario provincial portion, so never add them separately.
How do I remove tax from a total I already paid?
This tool only adds tax forward. To reverse it, divide the tax-inclusive price by 1 plus the rate as a decimal: at 13% HST, divide by 1.13. A $113 total is $100.00 before tax, so the tax portion is $13.00.
Does it handle Quebec's QST or other provincial taxes?
Yes, as long as you enter the right combined rate. For most Quebec purchases enter 14.975 (5% GST + 9.975% QST); for Manitoba or Saskatchewan, combine 5% GST with the provincial rate. The math is identical — only the number you type changes.
Frequently asked questions
Does this determine the correct tax rate?
No. Enter the rate that applies to your transaction and province.
Can this calculate a tax-inclusive price?
It calculates tax from a pre-tax amount. Divide a tax-inclusive price by 1 plus the rate to reverse the calculation.