Should You Invest or Pay Off Your Mortgage? A Canadian Guide

You have some extra cash every month. Maybe a raise, an inheritance, or just disciplined budgeting. The question almost every homeowner faces at some point: should that money go into investments or straight onto the mortgage? The answer is not as simple as comparing two numbers, but the math gives you a solid starting point.

The Core Question

At its simplest, this is a comparison between two rates. Your mortgage interest rate is the cost of keeping the debt. Your expected investment return is the potential reward for putting money to work elsewhere. If your investments earn more than your mortgage costs, investing wins. If they do not, paying down the mortgage wins.

But "simple" is doing a lot of heavy lifting there. Taxes, risk, account types, your personal comfort with debt, and the current interest rate environment all affect which option actually makes you wealthier over 10, 20, or 25 years.

Here is how to think through it properly.

The Math: Mortgage Interest vs. Investment Returns

In Canada, mortgage interest on your principal residence is not tax-deductible (unlike in the United States). That means your mortgage rate is the real, after-tax cost of your debt. A 5% mortgage costs you exactly 5%.

Investment returns, on the other hand, are subject to tax, unless they sit inside a registered account. The type of investment income matters too:

• Interest income (GICs, bonds, savings accounts): taxed at your full marginal rate. If you are in the 43% bracket in Ontario, a 5% GIC yields 2.85% after tax.
• Capital gains (stocks, ETFs): only 50% of the gain is included in your income (up to $250,000 annually; 66.67% above that as of 2024). Effective tax rate is roughly half your marginal rate.
• Canadian dividends: eligible for the dividend tax credit, which significantly reduces the effective rate. A 5% dividend yield might only cost 25% to 30% in effective tax for a middle-income earner.
• TFSA growth: zero tax. Ever. This is the key advantage.
• RRSP growth: tax-deferred. You pay tax on withdrawal, but contributions give you an immediate deduction at your current marginal rate.

This is why the question is not just "5% vs. 7%." It is "5% vs. 7% minus taxes, adjusted for risk, over your specific time horizon."

Tax-Sheltered Accounts Change Everything

The single biggest factor in this decision for most Canadians is whether you have room in your TFSA or RRSP. These accounts are so tax-efficient that they almost always tilt the math toward investing.

TFSA vs. Extra Mortgage Payments

If your TFSA has unused room, filling it before making extra mortgage payments is usually the stronger move, especially if your mortgage rate is under 5%. The tax-free compounding over 15 to 25 years is extremely powerful. A $7,000 annual TFSA contribution earning 6.5% grows to roughly $290,000 over 20 years, all tax-free.

RRSP Considerations

RRSPs are more nuanced. The contribution gives you an immediate tax refund, which is valuable, but withdrawals in retirement are taxed as income. The RRSP wins when your marginal tax rate at contribution is higher than your expected rate at withdrawal (which is common for peak-earning-years professionals who expect lower retirement income).

A smart hybrid: contribute to your RRSP, then use the tax refund as a lump-sum mortgage payment. On a $10,000 RRSP contribution at a 43% marginal rate, you get $4,300 back. Put that $4,300 on the mortgage. You have now deployed $10,000 into tax-sheltered investments and reduced your mortgage by $4,300, all from the same $10,000 of cash flow.

Scenarios: What Wins at Different Rates

Let us look at what happens with $500 per month of extra cash over 20 years, comparing investing in a balanced portfolio versus extra mortgage payments. We will assume a $400,000 mortgage with 20 years remaining.

Non-Registered Account (Taxable) vs. Mortgage Paydown

TFSA vs. Mortgage Paydown

The pattern is clear: in a TFSA, investing wins at virtually every mortgage rate because the returns compound tax-free. In a taxable account, the mortgage starts winning once rates push past 5%. This is why account type matters more than almost anything else in this decision.

The Guaranteed Return of Paying Down Debt

Every dollar of extra mortgage payment earns you a guaranteed, risk-free return equal to your interest rate. No investment in the world offers that certainty. The S&P/TSX has returned roughly 7% to 9% annually over the past 30 years, but that includes years where it dropped 30% or more.

If you have a 5% mortgage, paying it down is like finding a GIC that pays 5%, is government-guaranteed, and requires no account fees. You cannot lose money. You cannot have a down year. You simply owe less.

For people within 5 to 10 years of retirement, this certainty has real value. The last thing you want is to enter retirement with a large mortgage balance after a market correction wiped out the investment portfolio that was supposed to pay it off.

The Smith Manoeuvre (Brief Overview)

The Smith Manoeuvre is a strategy that attempts to make your mortgage interest tax-deductible by converting non-deductible debt into deductible investment debt. Here is how it works at a high level:

1. You get a readvanceable mortgage (a mortgage paired with a HELOC that automatically increases as the mortgage principal decreases).
2. Each time you make a mortgage payment, the available HELOC credit increases by the principal portion of that payment.
3. You borrow the newly available HELOC funds and invest them in income-producing assets (dividend stocks, for example).
4. Because the borrowed funds are used for investment purposes, the HELOC interest is tax-deductible under CRA rules.

Over time, your non-deductible mortgage shrinks while your deductible investment loan grows. In theory, you end up with a fully deductible loan and a growing investment portfolio.

The risks are real. You are leveraging your home to invest in the stock market. A sustained downturn means you owe money on investments that have lost value. The strategy works best for higher-income earners with stable employment, a long time horizon (15+ years), and genuine comfort with leveraged investing. It is not a casual decision and typically requires guidance from both a financial planner and a tax professional.

The Emotional Side of the Decision

Spreadsheets do not capture everything. For many Canadians, the mortgage represents the single largest financial obligation they will ever carry. The psychological weight of that debt is real, and the relief of eliminating it is real too.

Some people sleep better knowing their home is paid off, even if the math says they would be marginally wealthier by investing instead. That peace of mind has genuine value. If carrying debt causes you stress, if it affects your spending decisions or your ability to take career risks, then the "optimal" spreadsheet answer may not be the right answer for your life.

On the other side, some people feel anxious about missing out on market returns while they aggressively pay down a low-rate mortgage. Both responses are valid. The best strategy is the one you will actually stick with for 15 to 25 years.

How Current Rates Affect the Decision

The interest rate environment in 2026 has shifted the calculus compared to the ultra-low-rate era of 2020 to 2021. Here is how to think about it:

• If you locked in at 2% to 3% (2020-2021 era): Investing almost certainly wins. Your mortgage costs less than inflation. Even a conservative balanced portfolio should outpace your mortgage rate. Do not rush to pay this off. Max out your TFSA and RRSP first.
• If your rate is 4% to 5% (current market range): The decision is closer. TFSA investing still has an edge, but non-registered investing is roughly break-even. A hybrid approach makes sense.
• If your rate is 5.5%+ (some fixed-rate renewals, private mortgages): Paying down the mortgage is very competitive. The guaranteed 5.5%+ return is hard to beat on an after-tax basis, especially in a taxable account.

The Bank of Canada's policy rate trajectory matters too. If you are on a variable-rate mortgage and rates are expected to decline, your mortgage cost will fall over time, which makes investing more attractive. If rates are expected to rise, locking in the guaranteed return of mortgage paydown becomes safer.

The Hybrid Approach: Why Not Both?

The debate is usually framed as either/or, but most people benefit from doing both. Here is a practical framework:

1. Build an emergency fund first. Three to six months of expenses in a high-interest savings account. Non-negotiable. Do this before extra mortgage payments or investing.
2. Max out your TFSA. The tax-free growth is too valuable to pass up at almost any mortgage rate.
3. Contribute to your RRSP if your marginal rate is above 30%. Use the refund for a lump-sum mortgage payment.
4. Use remaining cash for extra mortgage payments. Most lenders allow 10% to 20% annual lump-sum payments plus increased monthly payments. Check your prepayment privileges at renewal.

This approach captures the tax advantages of registered accounts, the guaranteed return of mortgage paydown, and the liquidity of having accessible savings. It is not the absolute mathematical optimum for any single scenario, but it is robust across a wide range of outcomes.

One final thought: the best financial plan is the one that actually gets executed. If the complexity of optimizing between five different accounts and your mortgage causes paralysis, pick one strategy and start. Doing something with your extra cash is vastly better than leaving it in a chequing account while you debate the perfect allocation.