About TaxOptima and how we calculate

TaxOptima.ca is a set of free Canadian tax calculators and guides, made by Triple U Solutions. They are educational tools for homeowners and investors. We are not an accounting firm, law firm or financial adviser. Last reviewed October 18, 2026.

Where the numbers come from

Tax rates: the CRA's published 2026 federal and provincial brackets, with the Ontario surtax and the Quebec abatement. We cross-check the combined top rates against KPMG's published 2026 tables (including eligible and non-eligible dividends) and a test fails if they drift apart.
Capital gains: a 50% inclusion rate. The proposed increase to two-thirds was cancelled in March 2025.
Rules and examples: the Income Tax Act (paragraph 20(1)(c), sections 54 and 111), CRA Folio S3-F6-C1, Bulletin IT-533 and Singleton v. Canada (2001 SCC 61).
Interest rates: prime is 4.45% as of October 2026; HELOCs usually charge prime plus 0.2% to 1%. Defaults are examples: change them to your own.

How the Smith Manoeuver calculator works

It simulates the strategy month by month against a household that spends the same cash each month without borrowing to invest. Principal you repay is re-borrowed on the HELOC and invested; you pay the HELOC interest out of pocket; the refund (interest times your marginal rate) arrives yearly. Returns are assumed, pre-tax and not guaranteed. The old version of this calculator on this site did not charge the HELOC interest to the borrower and overstated the result; we rebuilt it and check it against a separately written implementation.

How we check our work

The mortgage payment is checked against the closed-form formula for semi-annual compounding.
The monthly projection is compared with a second, independently written implementation.
Tax functions are tested against hand-worked bracket calculations and the KPMG top-rate table.

What the calculators do not cover

Non-refundable credits, the alternative minimum tax, income-tested benefits, tax on investment returns inside the Smith Manoeuver projection, the lifetime capital gains exemption, the principal residence exemption, and the 2027 changes to Ontario's and Quebec's non-eligible dividend credits. Talk to a licensed Canadian CPA or CFP before acting.

Updates and corrections

We refresh the tax tables each January and whenever prime or the rules change. Found an error? Email [email protected] and we will check it and credit the correction.