Reverse Sales Tax Calculator

Already have the total including tax? Use this reverse sales tax calculator to find the original subtotal and the exact GST, HST, PST or QST amount included. Select any Canadian province or territory, with optional US sales tax formulas for cross-border work.

Mode
Subtotal → Total Total → Subtotal

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Results
Subtotal
Grand Total

Reverse Tax Examples by Province

Each example starts from a $100.00 subtotal and shows the total you would have paid — then reverses it back to the subtotal and tax, province by province.

Alberta (AB — GST 5%)

Paid 105.00 total? Subtotal is 100.00 (tax: 5.00).

British Columbia (BC — GST 5% + PST 7%)

Paid 112.00 total? Subtotal is 100.00 (tax: 12.00).

Manitoba (MB — GST 5% + RST 7%)

Paid 112.00 total? Subtotal is 100.00 (tax: 12.00).

New Brunswick (NB — HST 15%)

Paid 115.00 total? Subtotal is 100.00 (tax: 15.00).

Newfoundland and Labrador (NL — HST 15%)

Paid 115.00 total? Subtotal is 100.00 (tax: 15.00).

Nova Scotia (NS — HST 14%)

Paid 114.00 total? Subtotal is 100.00 (tax: 14.00).

Northwest Territories (NT — GST 5%)

Paid 105.00 total? Subtotal is 100.00 (tax: 5.00).

Nunavut (NU — GST 5%)

Paid 105.00 total? Subtotal is 100.00 (tax: 5.00).

Ontario (ON — HST 13%)

Paid 113.00 total? Subtotal is 100.00 (tax: 13.00).

Prince Edward Island (PE — HST 15%)

Paid 115.00 total? Subtotal is 100.00 (tax: 15.00).

Quebec (QC — GST 5% + QST 9.975%)

Paid 114.98 total? Subtotal is 100.00 (tax: 14.98).

Saskatchewan (SK — GST 5% + PST 6%)

Paid 111.00 total? Subtotal is 100.00 (tax: 11.00).

Yukon (YT — GST 5%)

Paid 105.00 total? Subtotal is 100.00 (tax: 5.00).

Reverse Tax Questions

How do I calculate the pre-tax price from a total? ▾

Enter the total amount you already paid — the one that includes tax — and select your province or state. The calculator works backwards through the tax formula to show the original subtotal and the exact tax amount.

Why would I need to reverse-calculate sales tax? ▾

This is useful when a receipt or invoice only shows a total and you need the pre-tax cost — for expense reports, bookkeeping, or splitting a bill where tax needs to be backed out separately.

Is reverse tax calculation exact? ▾

Yes. The calculator works backwards through the same rounding rules used for the forward calculation, so the result matches what a forward calculation on that subtotal would have produced, to the cent.

Can I go the other direction, from subtotal to total? ▾

Yes — use the sales tax calculator, linked at the top of this page, to add GST, HST, QST, PST, or US sales tax to a subtotal.