Mortgage Refinance Break-Even in Canada: Penalty Math and When It Pays (2026)

Short Answer: Breaking a mortgage to refinance only pays when the interest you save before the old term would have ended is larger than the prepayment penalty plus every refinance fee, with time to spare. On a labeled hypothetical $420,000 balance with 36 months left in the term, moving from a hypothetical 5.39% contract rate to a hypothetical 4.19% rate cuts the payment from $2,863.10 to $2,587.36 and saves $14,776.50 of interest over those 36 months. A three-months-interest penalty on that balance is $5,659.50, which the refinance beats comfortably. A simple interest-rate-differential estimate is $15,120.00, which the refinance does not beat inside the remaining term. Same house, same rates, opposite answer - decided entirely by which penalty your contract uses.

By Finance Editorial Desk | October 3, 2026

Educational only, not mortgage, financial, tax, or legal advice. Every rate, fee, and payment in this article is a labeled hypothetical chosen so you can verify the arithmetic. Real penalties depend on your mortgage contract, your lender's posted-rate method, and the exact discharge date. Get the penalty in writing from your lender before you sign anything.

1. What refinancing actually changes

Refinancing replaces your current mortgage with a new one before the term ends. You are not shopping for a lower payment in the abstract. You are buying out the rest of an old contract at a price set by that contract, then starting a new contract at today's rate.

That purchase price has three parts, and most refinance advertising mentions only the third:

• The prepayment penalty. The fee your current lender charges for ending the contract early. For many closed fixed-rate mortgages in Canada this is described in the contract as the greater of three months of interest or an interest rate differential amount. Variable-rate penalties are often described as three months of interest. Your contract wording controls, and lender calculation methods differ - which is why section 3 treats the two penalty shapes separately instead of pretending there is one national formula.
• The transaction fees. Discharge or transfer fees, legal costs to register the new mortgage, an appraisal if the new lender requires one, and title insurance where it applies. Amounts vary by lender, by province, and by whether the new lender covers any of them as an incentive. This article uses one labeled hypothetical fee total so the break-even math stays auditable; your real total goes in its place.
• The new interest cost. The rate on the new mortgage, applied to your balance for every month you hold it. This is the only part that can save you money, and it only saves money on a clock: the savings accumulate month by month, while the penalty and fees are paid on day one.

The break-even question is therefore a race. Savings arrive monthly. Costs arrive immediately. Refinancing pays only if the race is won before something ends the new mortgage early - a move, a sale, or the end of the comparison window you care about.

2. The comparison window: why 36 months, not the whole amortization

The single most common refinance mistake is comparing interest over the full 20- or 25-year amortization. That comparison flatters every refinance, because almost any lower rate wins over two decades. It is also the wrong window for a break decision, for two reasons.

First, your old mortgage does not run for 20 more years at today's contract rate. It runs to the end of its current term, at which point you would renew - and renewal needs no penalty at all. The honest question is narrower: what do you gain between now and the date the old term would have ended, compared with simply waiting and renewing then? Interest saved after that date is not a benefit of breaking; it is a benefit of whatever rate you negotiate at renewal, which is available to you either way.

Second, penalties are priced off the remaining term, not the remaining amortization. A lender's interest rate differential is roughly the rate gap multiplied by the balance multiplied by the time left in the term. The shorter the remaining term, the smaller the differential penalty - and the fewer months of savings you have to cover it. Both sides of the race shrink together as the term end approaches, which is why the answer flips sign from one month to the next for some households.

So the working rule for this article, and the one to use on your own numbers: compare interest saved over the months remaining in your current term, against the penalty plus fees. If the refinance wins inside that window, it wins outright - every month after renewal is gravy. If it only wins over 10 or 20 years, you are not looking at a refinance saving; you are looking at a renewal saving that you could have without paying a penalty.

3. The worked example: one household, one balance (labeled hypothetical)

Every figure below comes from one hypothetical household, computed once and reused through the article so you can check the math:

• Current balance: $420,000
• Current contract rate (hypothetical): 5.39% fixed, closed
• Remaining term: 36 months (3 years left of a 5-year term)
• Remaining amortization: 20 years
• New offer (hypothetical): 4.19% fixed for a new term, same 20-year amortization, no cash out, no change to the balance
• Refinance fees (hypothetical, all-in): $2,400 for discharge, legal, appraisal, and title costs combined - a placeholder for illustration, not a quote; replace it with your real figures
• No rate changes, no extra payments except where stated, clean amortization

Monthly payments from the standard loan formula in section 10:

Interest charged over the next 36 months, and the balance at the end of that window:

Two readings of that table matter. The cash reading: your payment falls by $275.73 a month, which feels like the saving. The balance reading: after 36 months you also owe $4,850.12 less, because a lower rate sends more of each payment to principal even when the payment itself is smaller. The true 36-month economic saving of the lower rate is the $14,776.50 of interest avoided - the payment difference and the balance difference are just that one number arriving in two pockets.

4. The penalty, shape one: three months of interest

The simplest penalty shape, and the one many variable-rate contracts and some fixed-rate contracts describe, is three months of interest on the amount prepaid:

Penalty = balance x contract rate / 12 x 3

On our hypothetical: $420,000 x 0.0539 / 12 x 3 = $5,659.50.

Add the hypothetical fees: $5,659.50 + $2,400 = $8,059.50 in day-one costs, against $14,776.50 of interest saved over the remaining term. Net benefit inside the honest window: $6,716.99 in favour of refinancing, before considering what the monthly savings do next.

Break-even timing makes the margin concrete. The interest saving starts at $420.00 in month one ($420,000 x (0.0539 - 0.0419) / 12) and shrinks slowly as the balance falls. At roughly $410 a month of average interest saving, the $8,059.50 cost stack is recovered in about 20 months - comfortably inside the 36-month window, with 16 months of pure gain after the line is crossed. Under a three-months-interest penalty, this refinance is a clear yes on the math. Section 8 covers the non-math reasons it might still be a no.

Hold the formula, because it is the fastest sanity check you own: three months of interest is roughly 1.34% of the balance at a 5.39% rate (three quarters of one percent of the balance per point of rate, times the rate). As a share of the balance it grows with your contract rate and is completely indifferent to today's rates. That indifference is exactly what the second penalty shape does not share.

5. The penalty, shape two: the interest rate differential

The interest rate differential, or IRD, tries to make the lender whole for the rate it loses. In simplified form:

IRD (simplified) = (contract rate - comparison rate) x balance x years remaining in term

The comparison rate is, loosely, the rate the lender could charge today for a term matching the time you have left. Lenders' exact methods vary - some use posted rates, some apply discounts to them, some discount the future interest to present value, and the differences can move the result by thousands of dollars. That is not a footnote; it is the reason you must get your own penalty quoted in writing rather than estimating it from an article, including this one.

Using today's hypothetical new rate as the comparison rate for illustration: (0.0539 - 0.0419) x $420,000 x 3 years = $15,120.00.

Now rerun the race. Day-one costs: $15,120.00 + $2,400 = $17,520.00. Interest saved over the remaining term: $14,776.50. The refinance loses $2,743.50 inside the honest window - it would need about 43 months of savings to break even at the early pace, and the window only has 36.

Notice the trap the two shapes set together. The IRD is largest precisely when rates have fallen the most - exactly when refinancing looks most attractive in advertising. A 1.20-point rate drop created $14,776.50 of potential saving and a $15,120.00 simplified differential penalty on the same balance, because both numbers are built from the same rate gap. Under an IRD contract, a falling-rate environment does not hand you the gap; it hands the gap to your current lender as a penalty and leaves you the fees to pay for the privilege. This is why two neighbours with identical balances and identical new offers can get opposite answers, and why "rates dropped, should I refinance?" has no useful answer until the penalty shape is known.

What if you keep paying the old payment on the new mortgage - sending the $275.73 difference to principal instead of spending it? Over 36 months at 4.19% with a $2,863.10 payment, interest falls to $49,596.69 and the balance reaches $366,525.25. Interest saved versus staying put rises to $15,407.75 and the head start compounds after renewal, because every future payment attacks a smaller balance. That narrows the IRD loss to about $2,112 inside the window and turns strongly positive over the following years - but it does not change the honest-window verdict, and it should not be used to rescue a refinance the basic test rejects. Treat accelerated payoff as a bonus on a refinance that already passes, not as the reason one passes.

6. The second worked example: a variable-rate penalty (labeled hypothetical)

Penalties bite differently on smaller balances and shorter horizons. Take a second hypothetical household: $310,000 balance, variable contract rate held at a hypothetical 5.10% for illustration, 22 months left in the term, quoted a hypothetical 4.35% fixed refinance.

Three-months-interest penalty: $310,000 x 0.0510 / 12 x 3 = $3,952.50.

Interest saving pace at the start: $310,000 x (0.0510 - 0.0435) / 12 = $193.75 in month one, shrinking as the balance falls and assuming - unrealistically but transparently - that the variable rate never moves during the window. Rough total over 22 months: about $4,100. Against $3,952.50 of penalty plus any fees at all, the refinance is underwater inside its honest window. The monthly payment would fall and feel like a win every single month while the household ends the term behind.

The lesson generalizes: a three-months-interest penalty costs about three months of your current interest. You recover it only by saving interest faster than one month of old interest per month for a sustained period - which requires a rate gap large enough, on a balance large enough, for long enough. Small balances with short remaining terms fail that test at almost any plausible rate gap. Big balances with long remaining terms pass it at surprisingly small gaps. The balance and the calendar decide more than the rate does.

7. Blend-and-extend: the penalty-free offer with a hidden price

When the penalty kills a refinance, lenders often counter with a blend: your rate is averaged between the old contract rate and today's rate, the term is extended, and no penalty is charged. It sounds like a compromise. Price it as what it is - a refinance where the penalty is collected slowly, inside the rate, instead of once at discharge.

On our main hypothetical, a simple blended rate for a fresh 5-year term might be presented near the average of 5.39% and 4.19%, around 4.79% (illustrative only; real blends weight the remaining term and the extension). Compare honestly over the next 36 months: at 4.19% you save $14,776.50 versus staying; at a hypothetical 4.79% you save roughly half that, about $7,400, because the rate gap halves. The blend "saved" you a $15,120 penalty by surrendering about $7,400 of the saving inside the window - and it restarts a full term at a rate above today's, so if you break again in year two, a fresh penalty clock is waiting.

Blends are not always wrong. If you expect to move within two years, avoiding a five-figure penalty can matter more than squeezing the rate. But price the blend the way you priced the refinance: interest saved over the honest window, against zero penalty and zero fees. A blend that wins that comparison is a reasonable product. A blend chosen because "no penalty" felt safer, without the comparison, is usually the most expensive option on the table wearing the cheapest costume.

Porting deserves the same treatment if you are moving: carrying your existing mortgage to a new property avoids the penalty entirely in many contracts, sometimes with a blend on any additional amount borrowed. If a move is driving your refinance question, ask about porting before you ask about breaking.

8. Beyond the math: the four checks that can veto a winning refinance

A refinance can pass the break-even test and still be the wrong move. Four checks catch most of the failures:

Will you actually stay? The savings arrive monthly; the costs are sunk on day one. Selling or moving again before the break-even month converts a winning refinance into a loss. Our main example breaks even in about 20 months under a three-months-interest penalty - and never breaks even inside the window under the simplified IRD. If a move within two years is plausible, the refinance needs a much wider margin than the arithmetic minimum.

Does the new mortgage re-extend your amortization? Restarting a 20-year remaining amortization at 25 years cuts the payment dramatically and quietly hands back interest for years. The payment drop is then partly a term extension, not a rate saving. Keep the amortization the same when you compare offers - our worked example holds it at 20 years on both sides for exactly this reason - and treat any payment drop from a longer amortization as borrowed, not saved. The mortgage payment calculator shows the payment at each amortization so you can hold it constant yourself.

What does the stress test say now? Refinancing with a new lender in Canada generally means qualifying again, including the federal stress test at the higher of your contract rate plus two points or the benchmark floor. Income changes, new debts, or a lower appraised value can shrink what you qualify for or kill the application after you have already paid to break the old mortgage. Sequence matters: confirm the new mortgage is approved and the penalty is quoted in writing before the old one is discharged. The mechanics are the same ones in our mortgage stress test guide.

Are you cashing out or consolidating into the new balance? Adding credit card or loan balances to a refinanced mortgage lowers the blended rate on that debt and can be legitimate - but it converts unsecured debt into home-secured debt and stretches consumer purchases across a mortgage amortization, where even a low rate collects interest for a very long time. We worked that trade in full in Debt Consolidation in Canada: Loan vs Balance Transfer vs HELOC. Run a refinance for rate reasons and a consolidation for debt reasons as two separate decisions with two separate break-even tests; a yes on one does not launder a no on the other.

9. Decision framework: which situation gets which answer

The row that surprises people most is the second one. "Rates fell a lot" feels like the strongest possible case for breaking a fixed mortgage. Under an IRD contract it is mechanically the weakest case per dollar of balance, because the differential grows with the same gap that creates the saving. Your best refinance candidates are boring ones: variable contracts, fixed contracts priced on three months of interest, or fixed contracts where today's comparison rate sits close to your contract rate for other reasons.

10. The formulas, so you can audit any offer

Monthly payment: with balance B, monthly rate r (annual rate / 12), and n payments remaining in the amortization,

Payment = B x r x (1 + r)^n / ((1 + r)^n - 1)

For our current mortgage: B = $420,000, r = 0.0539 / 12, n = 240, giving $2,863.10. For the refinance at 4.19%: $2,587.36. Our mortgage refinance calculator runs this comparison with your own rates and term, and the private mortgage penalty calculator estimates break costs for private-lender situations.

Interest saved over the window: run both mortgages month by month for the months left in your current term - interest each month is balance x r - and subtract. Closed-form shortcuts mislead here because the two balances diverge; the loop is the honest method, and it is how every figure in section 3 was produced.

Three-months-interest penalty: balance x contract rate x 3 / 12. It depends only on your balance and your old rate.

Simplified IRD: (contract rate - comparison rate) x balance x years remaining. Real lender methods add posted-rate conventions and sometimes discounting, which can raise or lower the figure. Use this only to understand the shape of your penalty; use your lender's written quote for the decision.

Break-even month: the first month where cumulative interest saved exceeds penalty plus fees. If that month falls after your term would have ended, or after you might plausibly move, the refinance fails the test that matters. For a renewal-shock comparison once you reach term end penalty-free, the mortgage renewal shock calculator shows what the new payment looks like at renewal rates.

11. Before you sign: a ten-minute audit

1. Get the penalty quoted in writing, with the discharge date it assumes. Penalties move daily with the balance and rates; a verbal estimate from last month is not a number.
2. Ask which penalty shape your contract uses - three months of interest, IRD, or the greater of the two - and, for IRD, which comparison rate and whether posted or discounted rates feed it.
3. List every fee on both sides: discharge, legal, appraisal, title, and any lender incentive that offsets them. Confirm incentives in the commitment, not in conversation.
4. Hold amortization constant across every offer you compare. Note any offer that quietly restarts the clock.
5. Compute interest saved over the months left in your current term only. Write down the break-even month.
6. Ask about porting if a move is anywhere in the picture, and about blends with the section 7 pricing in hand.
7. Confirm the new mortgage is fully approved - including stress test and appraisal - before instructing discharge of the old one.
8. Run your real balance, rates, and penalty through the mortgage refinance calculator and compare its break-even month with your own arithmetic from section 10.

12. Frequently asked questions

How much does it cost to break a mortgage in Canada? There is no single figure, because the cost is built from your balance, your contract rate, your penalty formula, and the time left in your term. In this article's labeled hypotheticals, a three-months-interest penalty on $420,000 at 5.39% is $5,659.50, while a simplified interest rate differential on the same mortgage is $15,120.00. Your contract and a written quote from your lender are the only sources for your real number.

What is the difference between an IRD penalty and three months of interest? Three months of interest depends only on your balance and your contract rate, so it stays fixed as market rates move. An interest rate differential depends on the gap between your contract rate and a current comparison rate, so it grows when rates fall - the very moment refinancing looks attractive. Many closed fixed-rate contracts charge the greater of the two; many variable-rate contracts charge three months of interest. Your mortgage terms say which applies to you.

How do I calculate my refinance break-even? Add the written penalty to every refinance fee. Then compute the interest you would save over the months remaining in your current term - not over the full amortization - by running both mortgages month by month. Divide the cost total by the early monthly interest saving (balance x rate gap / 12) for a rough break-even month, and check it against the exact schedule. Sections 3 to 5 work the full method on a $420,000 example.

Is refinancing worth it to lower my monthly payment? A lower payment alone does not answer the question, because payments also fall when amortization is extended, which can raise total interest even at a lower rate. In our worked example the payment falls by $275.73 a month with the amortization held at 20 years, and the refinance still loses money under an IRD penalty. Judge the move on interest saved inside the remaining term versus penalty plus fees, then enjoy the payment drop as a side effect if the test passes.

Should I blend and extend instead of refinancing? Price the blend as a refinance with no penalty and a higher rate: interest saved over the months left in your current term, compared against a true refinance and against simply waiting for renewal. Blends surrender roughly half the rate gap in our illustration and restart a full term, so they suit households that expect to move soon far better than households chasing maximum interest savings.

Can I refinance to consolidate credit card debt at the same time? You can, and the rate on the consolidated amount will usually fall, but the decision needs its own test: the debt becomes secured by your home and is stretched over a mortgage amortization, where it needs a fixed payoff plan to stay cheap. Our debt consolidation guide works a full $18,000 example across a loan, a balance transfer, and a HELOC. Passing the refinance test does not automatically make the consolidation wise, or the reverse.

What happens if rates fall further after I refinance? You hold the new contract you signed, with its own penalty terms if you break again. This is the practical argument for the honest-window test: a refinance that breaks even in 12 to 20 months has already banked its win before future rate moves matter, while one that needs 43 months is a bet that rates, your home, and your plans all stay still. The shorter the break-even, the less the future has to cooperate.

13. Related reading

• Mortgage Refinance Calculator - your balance, your rates, your penalty, and the break-even month computed directly.
• The Mortgage Stress Test (2026 Guide) - how qualification works when a new lender runs your application.
• Debt Consolidation in Canada: Loan vs Balance Transfer vs HELOC - the separate test for rolling other debts into the new mortgage.
• The Minimum-Payment Trap: The Exact Math (2026) - what unsecured balances cost while you wait for renewal.
• Browse all guides - calculators and explainers across finance, health, and math.

This article is educational and uses labeled hypothetical figures throughout. It is not mortgage, financial, tax, or legal advice for your situation. Penalty methods vary by lender and contract; confirm your figure in writing before acting.