How to Decide Between Investing and Paying Off Your Mortgage
Paying down your mortgage returns exactly your mortgage rate, guaranteed and after tax. Investing might return more or less, and the difference is risk. That single comparison settles most of this debate, and everything else is about your term, your tax situation and how you sleep at night.
It’s one of the most common questions Canadian homeowners ask once the mortgage is in place and there’s finally some money left over at the end of the month. There is no universal answer, but there is a reliable way to work out your own.
Key Takeaways
- A dollar put against your mortgage earns a guaranteed, risk-free, after-tax return equal to your mortgage rate, because mortgage interest on a principal residence is not tax-deductible in Canada.
- An investment has to beat your mortgage rate after tax and after fees to come out ahead, and it carries risk that the mortgage payment does not.
- High-interest consumer debt outranks both. Nothing in a portfolio reliably beats what a credit card charges.
- Prepayment privileges are capped annually and reset each year, so any unused portion is lost rather than banked.
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The Question Behind the Question
Most people asking whether to pay down the mortgage or invest are really asking a narrower question: what to do with a specific sum. A tax refund, a bonus, an inheritance, or a few hundred dollars a month that has appeared because a car loan finally ended.
That framing matters. It turns an abstract debate into an arithmetic problem with 3 inputs: what the mortgage costs you, what the alternative earns you after tax, and how much certainty you want. This article is about making that comparison. If you’ve already decided to attack the mortgage and want the tactics, our guide on becoming mortgage-free faster covers the mechanics in detail.
What Paying Down Your Mortgage Actually Returns
A lump sum applied directly to the principal reduces the balance on which interest is calculated for every remaining day of the loan. The saving is your mortgage rate, and 3 features make it unusual.
It’s guaranteed. Once the prepayment is made, the interest savings are locked in, and no market can take them back. It’s risk-free in a way that almost nothing in a portfolio is. And it’s effectively after tax, because interest on a mortgage secured by your principal residence is not deductible in Canada, so a dollar saved is worth a full dollar. An investment return, by contrast, is usually taxed at some point unless it’s sheltered.
The practical consequence is that the hurdle for investing is higher than it looks. A 4% mortgage doesn’t ask your portfolio to beat 4%. It’s asking your portfolio to beat 4% after tax, after fees, and reliably enough that you would still be comfortable if it did not.
What Investing Returns, and What It Costs
The case for investing rests on 2 things the mortgage cannot offer: the possibility of a higher return, and tax shelters that change the maths.
A Registered Retirement Savings Plan (RRSP) contribution generates a deduction now and is taxed on withdrawal, which is attractive if your income today is meaningfully higher than it will be in retirement. Our explainer on what an RRSP is covers how the deduction and the eventual tax interact. A Tax-Free Savings Account grows, and withdrawals are tax-free, with the contribution room restored the following year.
When an employer matches retirement contributions, the match is an immediate return that no mortgage rate can compete with. Skipping it to prepay the mortgage is usually a mistake.
The cost is uncertainty. Market returns arrive unevenly, and the sequence is not yours to choose. A portfolio that averages a good return over 20 years can still be down in the exact year you need the money. That’s precisely why the guaranteed side of this comparison carries more weight than a spreadsheet suggests.
When Paying Down the Mortgage Wins
- Your rate is high relative to what a low-risk investment pays, which makes the guaranteed return genuinely competitive.
- You are close to retirement and want the payment to stop before your income changes.
- Your income is variable, or your job is uncertain, and a smaller balance means a smaller payment at renewal.
- Debt keeps you awake. This is a real input, not a soft one, and a plan you abandon in a bad market returns nothing.
- You are early in the amortization period, when the interest portion of each payment is at its largest, and a prepayment does the most work.
When Investing Wins
- Your mortgage rate is low, which lowers the bar a portfolio has to clear.
- Your employer matches retirement contributions, and you are not yet capturing the full match.
- You have decades ahead of you, which is the one thing that makes market risk more tolerable.
- You have no emergency savings. Money locked into your home is hard to reach without borrowing it back, so liquidity comes first.
- Your registered contribution room is unused, and your current income sits in a high tax bracket.
One ordering rule sits above all of this. If you’re carrying credit card or unsecured debt at a double-digit rate, that comes first, ahead of both options. If the balances are large enough to be structural rather than temporary, consolidating them with your home equity may cost far less in interest than carrying them.
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How to Do Both Without Overthinking It
Splitting the money is not a failure to decide. For most households, it’s the better answer, because it captures some of the guaranteed return and some of the growth without betting the outcome on a forecast.
If you go that way, know the shape of your prepayment privileges before you move any money. Most closed mortgages allow a lump sum of a set percentage of the original principal each year, plus an increase to the regular payment amount, and lenders set those limits differently. The Financial Consumer Agency of Canada explains prepayment privileges, and the number that applies to you is in your mortgage agreement. Going past the limit turns a smart prepayment into a penalty.
Two habits do most of the work without requiring a decision every month. Switching to accelerated payments adds the equivalent of one extra monthly payment a year and shortens the amortization on its own. Increasing the regular payment by a modest percentage does the same thing more gradually. Run both through a mortgage payment calculator to see what each one does to how long it takes to pay off your mortgage.
What Changes at Renewal
Renewal is the one moment when a lump sum has no penalty attached and no privilege limit to respect. You can put down as much as you want against the balance on the maturity date.
It’s also the moment the comparison resets, because your rate changes. A term that renews at a meaningfully higher rate raises the guaranteed return on prepayment and makes the mortgage the stronger use of cash. A term that renews at a lower rate does the reverse. Reviewing this at every renewal, rather than deciding once and never revisiting it, keeps the strategy aligned with the actual numbers. If your maturity date is approaching, consider renewing your mortgage early before rates move again.
One caveat, stated plainly. nesto arranges mortgages and does not provide investment advice, so the investing side of this decision should be handled by a licensed financial planner or advisor who can see your whole picture.
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Frequently Asked Questions (FAQ) About Paying Down a Mortgage Versus Investing
Is it better to pay off my mortgage or invest in Canada?
It is better to pay off your mortgage when your rate is high relative to what a comparable low-risk investment pays. It is better to invest when your rate is low, your time horizon is long, or an employer pension or RRSP match is available. The comparison to run is your mortgage rate against the expected after-tax, after-fee return of the investment, since mortgage interest on a principal residence is not deductible in Canada.
Does paying down my mortgage lower my payment?
Paying down your mortgage usually shortens your amortization rather than lowering your payment, because a lump sum applied to principal leaves the regular payment unchanged and simply retires the balance sooner. Your payment typically resets at renewal, when the smaller balance is spread over the remaining amortization. That is when you benefit from a lower payment.
Should I use my RRSP refund to pay down my mortgage?
Using your RRSP refund to pay down your mortgage is a common strategy that captures the deduction and the guaranteed interest savings in the same year. It works best when the contribution was going to happen regardless, and the refund is treated as found money rather than as the reason for contributing. A financial planner, tax expert, or financial advisor can confirm whether the timing suits your tax situation.
Can I prepay as much as I want on my mortgage?
You cannot prepay as much as you want on a closed mortgage, because prepayment privileges are capped annually as a percentage of the original principal and exceeding the cap triggers a penalty. However, at renewal, you can pay down any amount without penalty. Open mortgages allow unlimited prepayment in exchange for a higher rate. Your exact limits are set out in your mortgage agreement.
Final Thoughts
The honest answer is that both options—prepaying your mortgage and investing—are good. That is the main reason this question generates so much argument and so little regret. A household that prepays consistently and a household that invests consistently both end up far ahead of one that does neither while waiting to be certain.
What tips the balance is your mortgage rate, and that number isn’t fixed for life. If your term is ending, nesto mortgage experts can show you what your options look like before you decide where the money goes.
Why Choose nesto
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