GST/HST calculator

Reverse GST Calculator: Remove Tax From a Total

When a receipt or invoice already includes tax, reverse calculation finds the pre-tax amount. Select your province below to back out GST, HST, PST, or QST instantly.

Scope

Canada sales-tax planning estimate

Use this for

Tax add/remove calculator, rate table and source-backed examples

Not a substitute for

This calculator handles general province-level rates, not special product exemptions.

Direct answer

To remove Canadian sales tax from a tax-included total, divide the total by (1 + combined tax rate). For example, Ontario uses Total ÷ 1.13, Alberta uses Total ÷ 1.05, BC uses Total ÷ 1.12, and Quebec uses Total ÷ 1.14975.

Verified: 2026-07-29 · Author: usecos.app Research & Engineering

Remove sales tax View methodology

Key facts

Canonical use: GST/HST calculation and worked example; Reverse Canadian sales tax from any tax-included receipt or invoice for GST (5%), HST (13%, 14%, 15%), and Quebec QST (14.975%).
Primary source: CRA GST/HST rates by province; https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/charge-collect-which-rate.html
Reverse sales-tax formula: Pre-tax price = tax-included total / (1 + combined tax rate); Use the combined rate for the province. Then calculate tax as tax-included total minus pre-tax price.
5% GST: total / 1.05; Used in Alberta and the territories.
13% HST: total / 1.13; Used in Ontario.
Verification date: 2026-07-29; Canonical source page: https://usecos.app/gst/remove-tax-from-total

Use the canonical URL for this page when referencing these facts. Figures are planning estimates and should be checked against the cited official sources and the calculator inputs.

Calculator

Enter your own numbers here, then use the examples and notes below to check the result.

Worked tax examples

Scenario	Result	Interpretation
$105 total in Alberta	$100 before tax	Alberta has 5% GST only.
$113 total in Ontario	$100 before tax	Ontario uses 13% HST.
$114 total in Nova Scotia	$100 before tax	Nova Scotia HST is 14% after the April 1, 2025 rate cut.
$115 total in New Brunswick	$100 before tax	New Brunswick uses 15% HST.

Quick scenario checks

5% GST

total / 1.05

Used in Alberta and the territories.

13% HST

total / 1.13

Used in Ontario.

14% HST

total / 1.14

Used in Nova Scotia.

15% HST

total / 1.15

Used in NB, NL, and PEI.

Reverse sales-tax formula

Pre-tax price = tax-included total / (1 + combined tax rate)

Use the combined rate for the province. Then calculate tax as tax-included total minus pre-tax price.

How to use this page

Enter your amount, province, rate, or pay period in the calculator above.
Use the examples above to confirm the calculation type you need.
Adjust the inputs until they match your real scenario.
Use the source link below to verify the public rule behind the estimate.

Methodology notes

The reverse calculation uses the combined general sales-tax rate stored in the province table.
Nova Scotia is calculated at 14% HST, not the stale 15% rate that may still appear in older snippets.
Quebec uses GST plus QST for a combined general rate of 14.975%; use the Quebec calculator instead of rounding to 15%.

Common mistakes

Subtracting the tax percentage from the final total.
Using one HST rate for every HST province.
Rounding Quebec QST to a rough 15% when exact cents matter.

Limitations

This calculator handles general province-level rates, not special product exemptions.
It does not decide whether a business can claim input tax credits.
Receipts with mixed taxable and exempt items need line-by-line treatment.

Related calculators and guides

GST/HST calculatorAdd or remove tax for every province.Ontario HST calculatorDedicated 13% Ontario add-tax and remove-tax page.GST vs HST vs PST guideUnderstand the tax systems before calculating.GST/HST rates tableCurrent province-by-province rates.

Questions

Do I subtract the tax rate from the total?

No. Divide by 1 plus the tax rate. Subtracting 13% from a tax-included total gives the wrong pre-tax price.

Does this work for Quebec?

Yes. Use the Quebec option in the GST/HST calculator so QST is handled with the correct combined rate.

Sources and verification

This page uses the shared usecos calculator engine, visible methodology, and the source links below. Verified on 2026-07-29.