Mortgage Prepayment Penalty in Canada: IRD vs Three Months' Interest (2026)

The Two Ways Canadian Lenders Calculate Your Penalty

If you break your mortgage before the end of its term, whether to sell, refinance, or switch lenders, your lender charges a prepayment penalty. Which formula applies depends on your mortgage type:

• Variable-rate mortgages: almost always three months' interest, full stop • Fixed-rate mortgages: the greater of three months' interest or the Interest Rate Differential (IRD)

That second rule is the one that surprises people. On a fixed mortgage, the lender always charges whichever number is bigger, and IRD is very often the bigger number when interest rates have dropped since you signed.

Three Months' Interest: The Simple Calculation

This one is straightforward: take your outstanding balance, multiply by your annual interest rate, divide by 12, then multiply by 3.

Example: a $500,000 balance at 5.25% works out to roughly $6,562. It is predictable, and it is the only penalty formula that ever applies to a variable-rate mortgage.

Interest Rate Differential (IRD): Why It Can Cost Far More

IRD exists to compensate the lender for the interest they lose when you pay off a fixed-rate loan early and rates have since fallen. In principle, it is the gap between your contract rate and the lender's current rate for your remaining term, multiplied by your balance and the months left.

The bigger that rate gap, the bigger your penalty. If rates have risen since you signed, IRD can come out near zero and you pay the three-month minimum instead. If rates have fallen, IRD can run into the tens of thousands of dollars on a large balance with several years left on the term.

Posted Rate vs Discounted Rate: Why the Same Math Gives Very Different Answers

The part most borrowers do not know: lenders do not all use the same "current rate" in the IRD formula.

Big Six banks (RBC, TD, Scotiabank, BMO, CIBC, National Bank) typically compare your contract rate against their posted rate, a rate almost nobody actually pays, rather than the discounted rate they actually offer new customers. That artificially widens the gap and inflates the penalty.

Monoline lenders (First National, MCAP, Strive, CMLS, and similar) generally compare against the rate they would actually offer today, producing a fairer, smaller number for the identical mortgage.

On the same $400,000 balance with a meaningful rate drop, a monoline IRD or three-month penalty typically lands in the $4,000-$5,500 range, while a Big Six posted-rate IRD on the same numbers can reach $15,000-$25,000.

When Breaking Your Mortgage Still Makes Financial Sense

A penalty is a cost, not necessarily a reason to stay put. Breaking early can still be worth it when:

• You are selling and moving regardless of the penalty • A refinance at a meaningfully lower rate saves more over the remaining term than the penalty costs • You are consolidating high-interest debt (credit cards, lines of credit) into the mortgage at a much lower blended rate • Only a few months remain on the term, so the penalty itself is small

Before deciding, run the actual math: total penalty cost versus total interest saved over the time you would otherwise have kept the old mortgage. A broker can pull real numbers instead of relying on a rough calculator.

How to Reduce or Avoid the Penalty

1. Port your mortgage: if you are buying a new property, many lenders let you transfer your existing rate and term to the new property instead of breaking and re-borrowing. This can eliminate the penalty entirely.

2. Blend-and-extend: some lenders will blend your old rate with a new, longer-term rate instead of charging a full penalty, useful if you want a lower rate but are not ready to switch lenders.

3. Time it to renewal: if your term is close to maturity, waiting even a few months can turn a large IRD into a small three-month penalty.

4. Get quotes before you commit: ask for a written penalty quote before listing your home, signing a refinance, or agreeing to switch lenders, not after.

How to Get an Accurate Penalty Quote

Online penalty calculators (including the one on your lender's own website) give estimates, not final numbers. For a number you can rely on:

• Call your lender directly and request a mortgage discharge statement or penalty quote in writing • Ask how long the quoted number is valid for, most are only good for a set number of days • If you are working with a broker, ask them to confirm the number with the lender before you commit to a closing date

The gap between an online estimate and your lender's actual quote can be hundreds or thousands of dollars, especially on a Big Six posted-rate IRD calculation.