Pay off the mortgage or invest? The Canadian answer
Two destinations for the same dollars: a guaranteed return at your mortgage rate, or a higher expected return that isn't guaranteed. The internet argues this in American terms — with a tax deduction Canada doesn't have. Here's the decision with Canadian facts, and the version that matters most: the one where retirement is getting close.
The short answer
- PrepayingGuaranteed ~4.85% after tax at current market rates — beats every GIC, risk-free
- InvestingHigher expected return, not guaranteed — cleanest inside a TFSA
- Canada twistNo interest deduction — your mortgage rate is fully after-tax
- Near retirementThe mortgage side gains weight — fixed payments vs a variable portfolio is the bad combo
The frame: certainty versus expectation
Prepaying a mortgage is buying a risk-free bond that yields your contract rate, after tax, guaranteed — at June 2026's market 5-year fixed of roughly 4.85% (TD 4.84%, RBC 4.89%, against the Bank of Canada's 6.09% posted benchmark), that's a better certain return than anything on our GIC table. Investing the same dollars in diversified equities offers maybe 6–8% nominal on average — an average that contains 2008 and 2022. The comparison is therefore never just rate-vs-rate: it's a guaranteed number against a distribution, and the right answer depends on how the gap compensates you for risk you'd actually have to sit through. The calculator reports that gap as a breakeven return — when your honest expectation only barely clears it, the guaranteed option is telling you something.
The Canadian facts that change the math
First and biggest: your mortgage interest is not deductible. The CRA's Interest is deductible only when borrowed money is used for the purpose of earning income from a business or property (CRA line 22100; Income Tax Folio S3-F6-C1). A mortgage on the home you live in earns no income, so its interest fails the test. means a principal-residence mortgage gives no tax break — unlike the US, where the deduction discounts the effective rate and tilts their articles toward investing. Second: the account doing the investing sets the bar. Inside a TFSA the comparison is clean; in a taxable account, annual tax drag raises the breakeven — at a 35% marginal rate, a 4.85% mortgage demands roughly a 5.9% pre-tax return just to tie. The practical hierarchy writes itself: employer match first, TFSA second, and only then is "taxable investing vs the mortgage" a live question — one the mortgage frequently wins. Third, the plumbing: prepayment privileges cap penalty-free lump sums (TD 15%/yr of original principal; Scotia and CIBC 10–20%; RBC 10% — their own pages), and past them FCAC's penalty rule applies: the higher of three months' interest or the The interest rate differential — roughly, the interest your lender loses by releasing you from an above-market rate for the rest of your term. FCAC's example shows it reaching four times the three-month-interest figure. .
The retirement version — where the answer hardens
For a 35-year-old, this is a cheerful optimization. Inside ten years of retirement it becomes risk management, for one structural reason: a mortgage payment is fixed, and a retiree's income is a portfolio. Carrying payments into retirement forces withdrawals whether markets are up or down — mechanically identical to a higher withdrawal rate, applied at the exact moment sequence risk does its damage. That's why "retire mortgage-free" is near-consensus among planners without being a law of nature: a small, low-rate balance against a large liquid portfolio can be carried deliberately; what fails is the unexamined version. The pre-retirement decade is also when the guaranteed 4.85% looks best against a portfolio that should be de-risking anyway — prepaying the house is a form of buying bonds. Retirees weighing the reverse trade — pulling equity back out for income — are why the HELOC and reverse-mortgage pages are next in this series.
The answer most households should actually run
Blend, with rules. Take any employer match (nothing else on this page returns 50–100% instantly). Fill the TFSA — it keeps the investing comparison clean and the money reachable. Then split the remainder between mortgage and investments on a schedule you won't renegotiate every market headline, drifting the mix toward the mortgage as retirement approaches — and let the calculator show what each split costs in expected dollars, so the robustness you're buying is priced rather than guessed. The one wrong answer is the common one: doing neither while deciding.
Frequently asked questions
Is it better to pay off the mortgage or invest in Canada?
There is no universal answer — there is a clean framework. Prepaying earns a guaranteed, after-tax return equal to your mortgage rate (~4.85% on a current market 5-year fixed); investing offers a higher expected return that arrives with drawdowns attached. Investing tends to win on expectation inside a TFSA over long horizons; the mortgage tends to win once tax drag, short horizons, or an honest look at your risk tolerance enter the picture. Run your numbers in the calculator — then read the retiree section above, because the answer changes with your date of birth.
Why does everyone say prepaying is a “guaranteed return”?
Because it is, mechanically: every $1,000 you prepay stops accruing interest at your contract rate, forever, with certainty — the financial equivalent of buying a risk-free bond yielding your mortgage rate, after tax. At today’s rates that’s a guaranteed ~4.85%, which no GIC currently matches. The catch is the comparison: equities’ expected 6–8% nominal is higher — the question is whether you’re paid enough for the risk and the lost liquidity, which is precisely what the breakeven number in the calculator measures.
Should I be mortgage-free before I retire?
It’s one of the few near-consensus positions in retirement planning, and the reason is risk math, not moralizing: a mortgage payment is a fixed obligation, and funding it from a variable portfolio forces selling in down markets — it effectively raises your withdrawal rate and amplifies sequence risk exactly when you’re most exposed. Carrying a low-rate mortgage into retirement against a large, liquid portfolio can be rational; carrying one because the renovation ran long is how plans break. If retirement is inside ten years, the prepay side of the ledger quietly gains weight.
Does it matter that Canadian mortgage interest isn’t deductible?
It’s the whole reason US articles mislead Canadians. The CRA permits interest deductions only where borrowed money is used to earn income (line 22100; Income Tax Folio S3-F6-C1) — a principal-residence mortgage fails that purpose test, so your rate is fully after-tax. American homeowners get a deduction that discounts their effective mortgage rate; you don’t, which makes prepayment structurally more attractive here. The deliberate exception — restructuring debt so the borrowing does earn income — is the Smith Manoeuvre, a sharper-edged strategy we’ll treat on its own page.
What if I get a windfall — lump sum on the mortgage or invest it?
Same framework, two extra checks. First, prepayment privileges: closed mortgages cap penalty-free lump sums per year — TD at 15% of original principal, Scotiabank and CIBC at 10–20% by product, RBC at 10% (banks’ own pages, June 2026); exceed them and FCAC’s rule kicks in — a penalty of the higher of three months’ interest or the interest-rate differential. Second, TFSA room: a windfall that fits inside unused TFSA room gets the clean tax-free comparison; one that would land in a taxable account faces drag that often tips the math toward the mortgage.
Can I do both?
Most households should. The blended pattern that survives contact with real life: capture any employer RRSP match first (an instant 50–100% return outranks everything), keep the TFSA funded for flexibility, and split what remains — some to the mortgage on a schedule, some to investments — with the mix drifting toward the mortgage as retirement approaches. The split costs a little expected value versus the spreadsheet-optimal answer and buys a lot of robustness; the savings rate doing the funding matters more than the allocation between two good destinations.
Educational reference, not financial advice. Rate context verified June 11, 2026 (TD and RBC rate pages; Bank of Canada posted 5-year conventional rate, series V80691335; policy rate 2.25%); tax framing per CRA line 22100 and Folio S3-F6-C1; penalty rule per FCAC; prepayment privileges per each bank's published pages — your contract governs. Investment returns are expectations, not promises. Model your own situation, ideally with professional advice.