Mortgage penalties in Canada, and the trap that quietly costs you thousands

About 1.15 million Canadian households renew their mortgage in 2026. Many will think about breaking early to grab a lower rate, then get blindsided by a penalty they never saw coming. Here is exactly how that penalty is built, and the one factor that decides whether it costs you $5,000 or $25,000.

There are only two ways a penalty is calculated

When you break a closed mortgage before the term ends, the lender charges a prepayment penalty. It is always one of two methods, and knowing which one applies to you is most of the battle.

1. Three months' interest

The simpler method. The lender takes your outstanding balance, multiplies it by your contract rate, and charges one quarter of that (three months' worth). On a $400,000 balance at 5%, three months' interest is roughly $5,000. Variable-rate mortgages almost always use this method only, which is one quiet advantage of going variable.

2. The interest rate differential (IRD)

The IRD is meant to compensate the lender for the interest they lose because you left early. In principle it is the gap between your contract rate and the lender's current rate for a comparable remaining term, multiplied by your balance and the months left. Fixed-rate mortgages are charged the greater of three months' interest or the IRD, so when rates have fallen, the IRD usually wins, and it can be brutal.

The real trap: posted rates vs the rate you actually got

Here is the part the bank would rather you not calculate. The Big-6 banks (RBC, TD, BMO, Scotiabank, CIBC, National) compute IRD using their posted rates, the sticker rates they almost never actually charge, instead of the discounted rate you signed at. That manufactured gap inflates the penalty enormously.

Monoline lenders (First National, MCAP, CMLS, nesto and similar) typically calculate IRD against the rate you really got. Same mortgage, same situation, very different penalty.

That is not a rounding difference. The penalty method, driven by where you borrowed, can swing the cost by five figures.

When breaking your mortgage is actually worth it

Breaking pays off only when the interest you would save over the remaining term is comfortably larger than the penalty. The math:

• Interest saved ≈ your balance × (current rate − new rate) × years left on the term.
• Net benefit = interest saved − the penalty.

With a fair-penalty lender and a meaningful rate drop, breaking often nets thousands. With a Big-6 posted-rate IRD, the penalty frequently swallows nearly all of the savings, which is precisely how it is designed. Always run both before you decide.

The 2026 rule change that works in your favour

As of November 2024, OSFI removed the requirement to re-qualify under the federal mortgage stress test when you switch lenders on a straight renewal, as long as your mortgage amount and amortization stay the same. Both insured and uninsured borrowers benefit. In plain terms: at renewal you can shop the whole market and move to a better lender without the test that used to lock you in. Roughly 56% of mortgage holders now plan to do exactly that.

A few habits that protect you:

• Start 120 days early. Most lenders will hold a rate up to four months before your renewal date.
• Never auto-renew on the letter your bank mails you. The first offer is almost never their best.
• Compare a switch to a monoline against staying put, including any penalty if you are leaving mid-term.

On a $600,000 mortgage, moving from a 5.25% posted rate to a 4.60% discounted rate saves about $3,900 a year, near $19,500 over a five-year term.

Common questions