Canada GST/HST calculator: add or reverse tax
Choose a province or territory, check which taxes apply, and calculate from a pre-tax price or a tax-inclusive total. All amounts are in Canadian dollars.
By Invoodle · Updated · General-rate references checked 2026-10-21
General-rate arithmetic on one common base. The default Ontario example assumes 13% HST applies. Check the province, supply date, registration, taxability and selected taxes for your actual case. This tool does not handle different taxable bases, special rates, rebates or mixed-rate items, or produce a complete tax invoice. It does not read or save invoice drafts.
General-rate references checked 2026-10-21. Choosing a province does not determine place of supply, registration or taxability. Historical rates and special cases need separate checking.
Check Ontario tax guidance: CRA: GST/HST and provincial rate table, current and historical
Use a decimal point, without commas or currency symbols; up to 2 decimal places.
Base, tax components and total
- Amount before tax
- $100.00
- HST at 13%
- $13.00
- Total selected tax
- $13.00
- Total including tax
- $113.00
Each component is rounded separately to cents, ties up. Reverse mode balances the base after rounding components from the unrounded common base. Estimates can differ from a receipt or another rounding method.
A calculation link includes the province, amount, mode and selected tax components. Recipients can read those values. Typing does not change this page’s URL.
Try a fictional Canadian-dollar example
Each assumes the selected standard taxes apply to the whole amount, with no other adjustments. These examples do not establish tax treatment.
| Input and selected taxes | Base | Tax components | Total |
|---|---|---|---|
| CAD 113 total, Ontario HST | CAD 100.00 | HST 13%: CAD 13.00 | CAD 113.00 |
| CAD 100 base, Quebec GST + QST | CAD 100.00 | GST 5%: CAD 5.00; QST 9.975%: CAD 9.98 | CAD 114.98 |
| CAD 100 base, Nova Scotia HST | CAD 100.00 | HST 14%: CAD 14.00 | CAD 114.00 |
General-rate references by province and territory
Checked 2026-10-21; these are not universal charges on every sale. The table shows default arithmetic components, without deciding where a supply is made or which taxes apply. Use historical authority tables for earlier supply dates.
| Province or territory | Default components | Official provincial / rate reference |
|---|---|---|
| Alberta | GST 5% | CRA rate table |
| British Columbia | GST 5% + PST 7% | British Columbia: general PST and exceptions |
| Manitoba | GST 5% + RST 7% | Manitoba Finance: general RST and pre-GST calculation base |
| New Brunswick | HST 15% | CRA rate table |
| Newfoundland and Labrador | HST 15% | CRA rate table |
| Nova Scotia | HST 14% | CRA rate table |
| Northwest Territories | GST 5% | CRA rate table |
| Nunavut | GST 5% | CRA rate table |
| Ontario | HST 13% | CRA rate table |
| Prince Edward Island | HST 15% | CRA rate table |
| Quebec | GST 5% + QST 9.975% | Revenu Québec: GST/QST calculation, rounding and document-rate limits |
| Saskatchewan | GST 5% + PST 6% | Saskatchewan: general PST and taxable supplies |
| Yukon | GST 5% | CRA rate table |
Official guidance for checking a real supply
- CRA: GST/HST and provincial rate table, current and historical
- CRA: place-of-supply rules and exceptions
- CRA: registration and small-supplier timing tests
- Revenu Québec: GST/QST calculation, rounding and document-rate limits
- British Columbia: general PST and exceptions
- Manitoba Finance: general RST and pre-GST calculation base
- Saskatchewan: general PST and taxable supplies
Moving from arithmetic to an invoice
Opening the editor does not transfer these figures or clear an existing draft. Review document mode, CAD currency, required particulars and tax settings. The editor has one general Tax total rather than dedicated Canadian tax-component fields.
Open invoice editorHow to add GST, HST or a separate provincial tax
For a base B and a selected rate r%, that component is B × r ÷ 100 before rounding. This calculator rounds each selected tax to cents, adds the components and then adds their sum to the base. It assumes every selected tax applies to the same entered amount.
For a fictional CAD 100 Ontario sale at an assumed 13% HST, the tax is CAD 13 and total is CAD 113. For a fictional Quebec sale with both taxes applicable, the same base produces CAD 5 GST and CAD 9.98 QST, totalling CAD 114.98 after separate rounding.
Reverse GST/HST from an inclusive total
Before rounding, base = total × 100 ÷ (100 + the sum of selected rates). Each component = total × its rate ÷ (100 + that sum). The calculator rounds each component, adds those rounded amounts and subtracts them from the entered total to balance the displayed base.
At an assumed 13% HST, a CAD 113 total contains CAD 100 before tax and CAD 13 HST. Taking 13% off CAD 113 gives the wrong base. Reverse mode needs a known rate and a total containing only the selected taxes on one common base; it cannot identify mixed tax treatment, tips or extra charges.
Rounding can change the reverse base by a cent
This display rounds each component once to cents, with an exact half-cent rounded up. In add mode the entered base stays fixed. In reverse mode the entered total stays fixed and the displayed base balances after component rounding. The component amounts add to total tax, and base plus tax adds to total.
On a fictional CAD 0.10 base with an assumed 5% GST and 9.975% QST, GST rounds to CAD 0.01 and QST to CAD 0.01, so total is CAD 0.12. A single combined-rate rounding step could give a different answer. Reversing a rounded total may not recover the original base exactly.
For example, reverse a CAD 100 total with both Quebec components selected: rounded GST is CAD 4.35, QST is CAD 8.68 and the displayed base is CAD 86.97. The base is a balancing amount, not an independently rounded quotient. Reconcile the original document and applicable rounding instructions before using an estimate for billing or reporting.
Check the supply before choosing the tax components
A province selector is a rate illustration, not a place-of-supply decision. Check the type of supply, applicable location rules, supply date, registration and any exemption or special treatment with the relevant authority. Recipient address can matter under some rules, but it is not a universal rule for all goods, services or digital supplies.
GST/HST and a separate provincial tax can have different taxability and registration rules. Deselect a component only after checking your case. Selecting none produces zero-tax arithmetic; it does not classify a sale as exempt, zero-rated or outside scope.
These are general-rate references, not a historical-rate selector or a complete list of product-specific rates, rebates and exceptions. Special rates, different taxable bases or mixed-rate items need a separate reviewed workflow. Use the linked current and historical authority guidance for the actual transaction date.
Registration and invoice preparation are separate checks
The calculator does not decide whether you must register, collect tax or claim an input tax credit. The small-supplier rules include timing and category-specific tests; a single revenue figure does not settle every case. Follow CRA and the relevant provincial guidance rather than treating the calculation as a registration answer.
Invoodle’s editor exports one general Tax adjustment and lacks dedicated Canadian registration fields or separate GST/HST and provincial tax controls. A percentage applies to item subtotal before the separate order discount. Calculator values are not transferred into a draft. Review mode, CAD currency, tax settings and required particulars before issue.
Revenu Québec’s calculation guidance says a combined 14.975% rate must not appear on the document attesting to the sale. The calculator’s rate arithmetic is not a reviewed GST/QST invoice layout; use a workflow that supports the required presentation and particulars.
General-rate references checked on 21 October 2026. These assumptions are for arithmetic on one common base. Check current and historical rates, supply rules, registrations, taxability and exceptions with CRA and the relevant provincial authority before billing or filing.
Frequently asked questions
How do I add GST or HST to an amount?
Choose the checked province or territory illustration and select only the applicable taxes. Multiply the base by each selected rate divided by 100, round each component to cents, then add the taxes and base. An assumed 13% HST on CAD 100 gives CAD 13 tax and CAD 113 total.
How do I calculate GST/HST backwards?
Before rounding, divide the inclusive total by 1 plus the sum of selected rates divided by 100. This tool calculates each tax component from the unrounded common base, rounds the components, then balances the displayed base to the entered total. It requires one base and the selected tax treatment to be known.
What HST rates are used for the province illustrations?
The references checked on 21 October 2026 show 13% for Ontario, 14% for Nova Scotia and 15% for New Brunswick, Newfoundland and Labrador, and Prince Edward Island. These general-rate illustrations do not decide applicability or historical transition treatment.
Is QST calculated on the GST-inclusive price?
For the general illustration where both apply, GST at 5% and QST at 9.975% use the same pre-tax sale price. Revenu Québec explains separate and combined calculation methods and document-rate restrictions. This tool rounds each component separately; its result is not a complete GST/QST invoice.
Can I turn off PST, RST, QST or GST/HST?
Yes, for the arithmetic after checking which taxes apply. GST/HST and provincial tax treatment can differ. A zero-tax calculation does not establish an exemption or a registration conclusion. Changing the province resets the selection to all its listed standard components.
Why can my receipt differ by a cent?
Separate component rounding, item-by-item rounding, different tax bases or different treatment can produce a different result. The displayed reverse base is the entered total minus the rounded component amounts. Check the original document and official instructions rather than changing a tax record to match an estimate.
Does the calculator save my draft or update the URL?
Typing, selecting taxes and trying examples do not read or write saved invoice drafts or change the page URL. Copy calculation link explicitly includes the province, amount, mode and selected taxes. Recipients can read those values. Opening the editor does not transfer them.