What does reverse tax mean for Canada?

Reverse tax here means you start with a tax-inclusive total and estimate the pre-tax base and included tax. Federal GST, provincial HST in participating provinces, and Quebec GST plus QST all use the same core relationship: total equals pre-tax times one plus the effective rate.

When should I use HST versus GST plus QST?

Use HST math when the whole transaction is billed under a single harmonized rate, such as the Ontario HST rate published for standard taxable goods. Use Quebec GST plus QST when the sale follows the usual stacking rules described by Revenu Québec; this site uses one combined reference rate on the Quebec calculator for quick estimates.

Does CalcLook provide Canadian tax advice?

No. CalcLook publishes reference calculators and guides. Confirm the rate, exemptions, rebates, and rounding rules that apply to your invoice with official guidance or a qualified professional before relying on any estimate.

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Canada Reverse Tax Guide

Navigate GST, HST, and Quebec GST plus QST when a price already includes tax. Learn how Canada reverse tax math maps to CalcLook calculators, CRA rate references, and the divide-by formula for tax-inclusive totals.

How Canada fits the tax-inclusive model

Many Canadian retail prices and invoice lines already include tax. To back out the pre-tax amount, divide the total by 1 + r, where r is the effective rate expressed as a decimal. That pattern holds for GST, HST, and the common GST + QST stack in Quebec when your receipt behaves like one combined multiplier on the net price.

Pick your province or topic

Quebec reverse tax calculator for GST and QST estimates with a 14.975% combined reference rate.
Ontario HST reverse calculator for standard Ontario HST-inclusive totals.
How to reverse GST and QST for a step-by-step narrative before you plug numbers in.
How to calculate HST backwards if you want Ontario-specific steps and examples.

Official references and broader context

Open the government pages below to confirm the rate and rules for your purchase, then use CalcLook to work through the divide-by math. We also list the sources we rely on on the sources page, and we explain what CalcLook is (and is not) on the disclaimer page.

Canada Revenue Agency — GST/HST calculator (and rates) (provincial and territorial GST, HST, and Quebec QST percentages in one CRA table).
Revenu Québec — Basic rules for applying the GST/HST and QST, including how QST applies on the price excluding GST.
Ontario.ca — Harmonized Sales Tax (HST) overview, including Ontario's published HST rate and rebate information.

For the mental model behind division instead of subtracting a percentage from the gross, read tax-inclusive pricing and the shared reverse tax formula reference.

FAQ

What does reverse tax mean for Canada?: Reverse tax here means you start with a tax-inclusive total and estimate the pre-tax base and included tax. Federal GST, provincial HST in participating provinces, and Quebec GST plus QST all use the same core relationship: total equals pre-tax times one plus the effective rate.
When should I use HST versus GST plus QST?: Use HST math when the whole transaction is billed under a single harmonized rate, such as the Ontario HST rate published for standard taxable goods. Use Quebec GST plus QST when the sale follows the usual stacking rules described by Revenu Québec; this site uses one combined reference rate on the Quebec calculator for quick estimates.
Does CalcLook provide Canadian tax advice?: No. CalcLook publishes reference calculators and guides. Confirm the rate, exemptions, rebates, and rounding rules that apply to your invoice with official guidance or a qualified professional before relying on any estimate.