What It Actually Costs to Break Your Mortgage Early

Breaking a mortgage before the end of its term costs you a penalty, and the size of that penalty depends almost entirely on one thing: whether your contract rate is higher or lower than what the lender could charge today. On a variable-rate mortgage the answer is usually simple, three months' interest. On a fixed-rate mortgage you pay the greater of three months' interest or the interest rate differential, and the difference between those two numbers can be a factor of two or more.

Selling, refinancing, or just wondering what your current mortgage would cost to unwind? Book a call and we will walk through the numbers on your specific mortgage before you commit to anything.

The two formulas

Three months' interest. Your outstanding balance multiplied by your contract rate, divided by four. On $500,000 at 5 per cent that is $6,250. It is easy to calculate and easy to predict.

The interest rate differential, or IRD. The lender compares your rate to the rate it could charge today on a term similar to the time you have left, and bills you roughly the difference multiplied by your balance multiplied by the remaining months. The idea is to compensate the lender for the interest it will not earn because you left early and it has to re-lend the money at a lower rate.

Notice the asymmetry. If today's rates are higher than your contract rate, the lender loses nothing by you leaving, so the IRD is nil and you pay the three-month figure. If today's rates are lower, the IRD can be several times larger. Your penalty is essentially a call option the lender holds on your rate, and it only pays off for them when rates fall.

Two borrowers, same balance, very different bills

Both have $500,000 outstanding and 30 months left on a five-year fixed. The comparison rate is the best five-year fixed available in Canada as of August 21, 2026, which Ratehub put at 4.09 per cent for a high-ratio mortgage. The contract rates below are illustrative of common vintages, not quoted from any particular lender.

Our calculation. Comparison rate: Ratehub, best five-year fixed in Canada, August 21, 2026. Every lender's contract wording differs, so treat this as the shape of the problem rather than a quote.

The posted-rate problem

There is a second layer that catches people. Lenders calculate the IRD two ways. A discounted calculation compares your contract rate to today's rate on a comparable term, less the discount you originally received. A standard calculation compares your contract rate to the lender's posted rate, which is the sticker rate almost nobody actually pays.

Posted rates sit well above the rates lenders actually write, so a posted-rate calculation widens the gap and inflates the penalty. Big banks generally use the posted method; many monoline lenders use the three-month method on fixed mortgages full stop. This is one of the clearest cases in consumer finance of a term that costs nothing at signing and a great deal later, and it is priced into the rate you were offered whether or not anyone explained it. If a lender's rate is a few basis points better than the competition, the prepayment clause is usually where they got it back.

Your mortgage commitment and your annual statement both set out the method. It is worth finding before you need it, not after.

If you are working through a mortgage decision, these go with this one:

• Renewing Your Mortgage in 2026: The 120-Day Playbook
• The Mortgage Stress Test in 2026: What It Is and What It Costs You
• What a Real Estate Lawyer Actually Does, and When to Call One

Five ways to make the number smaller

Use your prepayment privileges first. Most mortgages let you pay down 10 to 20 per cent of the original principal each year without penalty. Do that immediately before you break, and the penalty is calculated on the smaller remaining balance. On a large IRD this alone can save four figures.

Port the mortgage. If you are buying another property, porting carries the existing rate and terms to the new place and avoids the penalty entirely. It comes with its own conditions and timing traps, which is a subject of its own.

Blend and extend. The lender averages your existing rate with a current one over a new, longer term. No penalty is charged up front, though the cost has not vanished, it has been folded into the blended rate. Ask what rate you would be offered as a new client and compare.

Wait for maturity, or close to it. The IRD shrinks as the remaining term shrinks, because there are fewer months of forgone interest to compensate. Inside the last few months of a term, the three-month figure usually takes over and the penalty becomes predictable. Many lenders will also let you lock a renewal rate 120 days out.

Check for a cash-back clawback. If you took cash back at signing, breaking early normally means repaying a prorated share of it on top of the penalty. That is a separate line item, and it surprises people.

When paying the penalty is the right answer

A penalty is not automatically a reason to stay put. It is a cost, and costs get compared to benefits. The simple version: divide the penalty by the monthly interest saving from the new rate, and you get the number of months it takes to break even. If that number is comfortably shorter than the time you plan to keep the mortgage, breaking is the better decision.

Borrower B above, paying $15,000 to move from 5.29 per cent to 4.09 per cent on $500,000, saves roughly $6,000 in interest in the first year. Break-even lands around thirty months, which is exactly the time remaining, so on those numbers it is close to a wash and the decision turns on other things: whether they are moving anyway, whether the new lender charges legal and appraisal fees, whether they value the certainty. Borrower A, whose penalty is $2,738, has a much easier decision if there is any reason at all to move.

Where this logic breaks down is when the penalty is being rolled into a new, larger mortgage. Financing a penalty makes the monthly cost look painless while quietly extending the amortisation and increasing the total interest paid. The break-even math still works, but you have to run it on the total cost, not the payment.

What would change the read

Rates. The Bank of Canada's policy rate has been 2.25 per cent through six consecutive holds, with the next decision on September 2, 2026. If fixed rates drift lower from here, IRDs on 2023 and 2024 vintage mortgages get larger, not smaller, and waiting costs more. If rates back up, the opposite happens and today's expensive penalty quietly shrinks. Nobody gets to know which, which is a good argument for finding out your lender's calculation method now and running the break-even with real numbers rather than a rule of thumb.

The penalty is only half the question. The other half is what you are getting for it, and that answer is different for a sale, a refinance and a switch. Book a call and we will run your actual balance, rate and remaining term against the alternatives, and tell you when the answer is to leave the mortgage exactly where it is.

Dave Dubbin
Real Estate Expert
Dave Dubbin & Associates
Real Estate Broker for Etobicoke and Toronto Sotheby's International Realty, Canada