25 vs 30-Year Mortgage in Canada: How Much Extra Interest Do You Actually Pay?
2026 Edition
You have probably heard this before: “Take the 30-year and just pay it like a 25. You get the flexibility and it costs the same.”
That sounds smart. It feels smart. It is also how borrowers end up paying thousands extra in interest without fully understanding how it happened.
A 30-year amortization is not a free flexibility option. It is a trade-off. Lower payments today in exchange for higher long-term cost. That trade can be the right call — but only when made deliberately. Most of the time it is made by default, and default is expensive.
Quick Answer
On a $600,000 Canadian mortgage, choosing a 30-year amortization at 4.25% instead of a 25-year at 4.00% costs you approximately $111,061 more in total interest. The monthly payment difference is only $218 — but you pay it for 60 extra months, at a higher rate. The 30-year can make sense for variable-income borrowers or first-time buyers qualifying under the stress test, but it should be a deliberate choice, not a default.
The Rate Is Not the Same
The first place the “pay it like a 25” argument breaks down is the rate itself.
Most lenders charge a premium for 30-year amortizations — typically 0.20% to 0.25% above the equivalent 25-year rate. The reason is straightforward: a longer loan means more risk for the lender, and they price accordingly.
This premium is rarely discussed when the payment comparison comes up. But on a $600,000 mortgage, that gap alone adds $30,000 to $40,000 in extra interest — before you account for the additional five years of payments. You are not comparing two versions of the same loan. You are comparing a cheaper loan to a more expensive one.
| Lender | 25-Year Rate | 30-Year Rate | Spread |
|---|---|---|---|
| Big 5 Banks (avg) | 4.04% | 4.29% | +0.25% |
| BMO | 3.99% | 4.24% | +0.25% |
| TD | 4.14% | 4.39% | +0.25% |
| RBC | 4.09% | 4.34% | +0.25% |
| Monoline Lenders (avg) | 3.89% | 4.09% | +0.20% |
| Credit Unions (avg) | 3.94% | 4.19% | +0.25% |
Why this matters: A 0.25% rate premium does not sound like much. But on a $600,000 mortgage over the full amortization, that quarter-point is responsible for roughly $30,000–$40,000 in additional interest — before you even account for the extra five years of payments. Rates shown are representative of April 2026 market conditions and will vary by qualification profile.
What the Numbers Actually Look Like
On a $600,000 mortgage, using Canadian semi-annual compounding:
25-Year at 4.00%
30-Year at 4.25%
The 30-year costs you
$111,061 more
in total interest — and you are making payments for five extra years
That is the trade in plain numbers. $218 less per month today, $111,061 more over the life of the mortgage. Whether that trade makes sense depends entirely on what you do with the $218 and whether the lower payment solves a real problem in your current situation.
Why “Pay It Like a 25” Rarely Works in Practice
The math of this strategy is correct. The behavior is not.
If the rate were identical and you consistently applied the difference to your mortgage every single month for 25 years, you could match the 25-year outcome. The problem is what actually happens.
You move into a new home. Furniture, repairs, and upgrades absorb cash you did not expect to spend. Income fluctuates. A vacation happens. A child arrives. The extra payment you planned on making shifts from consistent to occasional to forgotten.
I have watched this pattern over many years. The intention to pay extra is real at signing. The execution fades within the first twelve to eighteen months in most cases. The 30-year stops being a strategy and becomes the actual amortization.
As From Debt to Zero puts it, “the borrower is servant to the lender.” The longer you stay in the system, the more it benefits the bank. Staying longer is the default outcome when a plan depends on sustained discipline that was never tested before.
The flexibility argument also hits a wall with real lender rules. BMO, for example, limits prepayments to 20% of the original principal as a lump sum plus a 20% increase to your regular payment per calendar year. You cannot just double your payment whenever you want — there are contractual caps. TD has similar limits. Scotia's are even tighter on some products.
Bottom line: “Take 30, pay like 25” only works if you can get rate parity — same rate for both amortizations. Some credit unions and monoline lenders occasionally offer this. If your lender charges a premium for 30 years (most do), the math does not favour you. Ask your broker to quote both amortizations at the same rate and see if the lender agrees.
When a 30-Year Is Actually the Right Call
The 30-year is not a bad product. It is a misused one. There are situations where the lower payment is the correct priority and the extra cost is worth it.
A First-Time Buyer on the Edge of Qualifying
That $218 difference is not abstract. It may be the gap between entering the market this year for the right property or waiting another two years while prices move further out of reach. In that context, the higher long-term cost may be the correct trade.
Variable Income
If you are self-employed, work on commission, or have seasonal income, the lower mandatory payment gives you real buffer during slow periods. You can still accelerate payments when income is strong. But you are not committed to the higher amount during months when cash is tight.
Building an Emergency Fund First
A borrower who takes a 25-year and depletes their cash reserve to manage payments is in a worse position than a borrower who takes a 30-year with three months of expenses in savings. The interest cost difference matters less than the financial stability difference when something unexpected happens.
The 30-year becomes a problem when none of these conditions apply and the decision is made because the payment feels better. That is taking a more expensive mortgage to avoid thinking carefully about affordability.
The TFSA and Investment Argument
The counterargument to paying down faster is investing the difference. The math does work.
The Scenario
At 6.5% average annual return, investing $218 per month over 25 years in a TFSA produces roughly $163,246. After accounting for the $111,061 in extra mortgage interest, you come out ahead by approximately $52,185.
Monthly Investment
$218
After 25 Years (6.5%)
~$163,246
Extra Interest Paid
~$111,061
The honest question is whether you will actually invest that $218 consistently for 25 years.
If you have a disciplined investment habit already in place, this argument has merit and is worth running with your real numbers. If you have not been investing consistently before this decision, the odds of starting now and sustaining it for 25 years are not high. In that case, the extra mortgage paydown is the more reliable path to the same outcome, because it happens automatically with every payment.
The honest answer: The strategy only works if the behavior is already there. A guaranteed 4%+ return with zero risk is hard to beat for borrowers who are not already disciplined monthly investors.
What Happens at Renewal Matters More Than People Realize
One detail that regularly catches borrowers off guard: if you take a 30-year amortization with the plan to shorten it at renewal, that plan depends on where you renew.
Staying with Your Lender
- Can shorten or extend amortization
- No new stress test required
- No legal fees or appraisal needed
- Can negotiate rate as part of the renewal
Switching to a New Lender
- Full B-20 stress test requalification
- May need new appraisal ($300–$600)
- Can choose any amortization you qualify for
- Access to potentially better rates
If you stay with your current lender, you can typically shorten your amortization at renewal without requalifying. That is a real option and the flexibility argument for a 30-year has some validity here.
If you switch lenders at renewal, you will requalify under the current stress test. Switching lenders would also allow you to shorten your amortization — please double-check with the new lender. If rates have risen significantly and your GDS/TDS ratios are tight, this may limit your options. This is a real trap that catches people who focus only on rate-shopping at renewal.
Which One Fits Your Situation?
Choose 25 years if…
Your goal is straightforward: minimize total interest and exit the mortgage as efficiently as possible. If your cash flow is stable and you do not need the buffer, the 25-year is almost always the lower-cost path.
- Your income is stable and predictable (salaried, dual-income)
- You have an emergency fund (3–6 months) to handle disruptions
- Your mortgage rate is above 4% (the TFSA arbitrage disappears)
Choose 30 years if…
You have a specific reason for needing the lower payment — and a plan to compress the amortization at renewal when your situation allows.
- You need it to qualify for the right property as a first-time buyer
- Your income is variable (self-employed, commission, contract work)
- You are building a financial reserve before tightening your budget
- You have a concrete plan to shorten the amortization at first renewal
The worst outcome is not choosing 25 or 30. It is choosing 30 by default — because the payment felt better — without running the real numbers, and discovering what that choice cost ten years later.
Common Questions
Related Guides
True Cost of a Canadian Mortgage
APR vs stated rate, CMHC premiums, and everything the rate sheet hides.
Payment Shock: Renewing from 1–2% to 4%+
What happens to your payment when rates double — and 5 strategies to soften the blow.
The 2026 Renewal Trap
$900B+ in mortgages renewing at 2–3x original rates. Your 120-day action plan.
Camilo Rodriguez
Founder of Mortgages Lab & Mortgage Expert
Camilo Rodriguez is the Founder of Mortgages Lab, a licensed mortgage broker with over 23 years of experience helping Canadians achieve financial freedom. He has trained 100+ mortgage agents across Canada and is Past President of The Canadian Mortgage Broker Association - BC. He is the author of "From Debt to Zero," a guide to becoming mortgage free.
P.A.Y.O.F.F™, L.A.B™, M.A.P™ are Trademarks of Mortgages Lab®
Financial Disclosure
This page contains informational content only and does not constitute financial advice. Mortgage rates shown are sourced from publicly available lender data and may change without notice. Always verify rates directly with the lender. Mortgages Lab may receive compensation from partner lenders, which does not influence our editorial content or rate rankings. Built on Real Experience — 23+ years of working with real mortgage scenarios and helping Canadians achieve financial freedom.
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