Reverse HST and Sales Tax Calculator
Have a tax-included total? Find the price before tax and exactly how much GST, HST, PST or QST is inside it, for any province or territory.
Current 2026 rates, verified October 9, 2026
Use the province where the item is delivered or the service is provided.
The reverse sales tax formula
Pre-tax price = Total ÷ (1 + tax rate)
Then Tax = Total − Pre-tax price. With 13% Ontario HST on a $226.00 total: $226.00 ÷ 1.13 = $200.00 before tax, and $26.00 HST.
Divisors by province
| Province / territory | Rate | Divide total by |
|---|---|---|
| Alberta | 5% | 1.05 |
| British Columbia | 12% | 1.12 |
| Manitoba | 12% | 1.12 |
| New Brunswick | 15% | 1.15 |
| Newfoundland and Labrador | 15% | 1.15 |
| Nova Scotia | 14% | 1.14 |
| Ontario | 13% | 1.13 |
| Prince Edward Island | 15% | 1.15 |
| Quebec | 14.975% | 1.14975 |
| Saskatchewan | 11% | 1.11 |
| Northwest Territories | 5% | 1.05 |
| Nunavut | 5% | 1.05 |
| Yukon | 5% | 1.05 |
Frequently asked questions
How do I calculate tax backwards?
Divide the total by 1 plus the tax rate. For 13% HST, divide by 1.13. For 5% GST, divide by 1.05. The result is the pre-tax price; subtract it from the total to get the tax.
Why can't I just subtract 13% from the total?
Because the 13% was calculated on the smaller pre-tax price, not on the total. Subtracting 13% of the total removes too much. On $113, subtracting 13% gives $98.31 instead of the correct $100.00.
How do I extract GST from a receipt in BC, Saskatchewan or Manitoba?
First divide the total by 1 plus the combined rate (1.12 in BC and Manitoba, 1.11 in Saskatchewan) to get the pre-tax price. Then GST is 5% of that pre-tax price, and the provincial tax is the rest.
Why might my result be one cent off a receipt?
Retailers round each tax to the nearest cent, sometimes per item rather than on the total. Small one-cent differences are normal when working backwards.
All rates and amounts on this page are taken from official government sources, including the Canada Revenue Agency, Revenu Québec and provincial and territorial finance ministries. Last verified October 9, 2026.