Mortgage Prepayment Penalties and IRD in Canada, Explained (2026)

If you break a closed mortgage before the term ends — to refinance, sell, or switch lenders — you'll almost always pay a prepayment penalty. On a variable mortgage it's small and predictable. On a fixed mortgage it can run to five figures and blindside borrowers who never read the fine print. In 2026, with many Canadians weighing whether to break older mortgages, understanding how the penalty (especially the interest rate differential, or IRD) is calculated is worth real money. Here's the full picture.

The short answer

There are two common prepayment penalties. Three months' interest applies to variable-rate mortgages, and to fixed mortgages when it works out larger. The interest rate differential (IRD) applies to fixed-rate mortgages and is the lender's estimate of the interest it loses for the rest of your term. On a fixed mortgage you pay the greater of the two. Big banks often calculate IRD using inflated "posted" rates, which can make their penalty several times larger than a monoline lender's. Before breaking, get the exact figure from your lender and run a break-even.

Why prepayment penalties exist

When a lender gives you a closed mortgage at a fixed rate, it has effectively planned its own funding around collecting that interest for the full term. If you pay the mortgage off early — or refinance into a lower rate — the lender loses the interest income it was counting on. The penalty exists to compensate for that loss. That's also why an open mortgage carries no penalty (you pay for that flexibility with a higher rate) and why variable penalties are mild: the lender's funding cost floats with the market, so its loss when you leave is limited.

The two common penalties

Three months' interest

This is the simple one. The lender takes roughly three months of interest on your current balance at your current rate. On a $400,000 balance at 5%, that's about $5,000 (400,000 × 5% × 3 ÷ 12). It's predictable and small, and it's the penalty on virtually all variable-rate mortgages.

Interest rate differential (IRD)

The IRD reflects the interest the lender forgoes for the months remaining on your fixed term because rates have changed since you signed. In rough terms it's the difference between your rate and a comparison rate, multiplied by your balance, applied over the time left:

IRD ≈ (your rate − comparison rate) × balance × (months remaining ÷ 12)

The bigger the gap between your rate and current rates, and the more term remaining, the larger the IRD. On a fixed mortgage you pay whichever is greater — three months' interest or the IRD.

Why big-bank "posted rate" IRD is so much larger

The single most important detail in an IRD calculation is the comparison rate the lender uses — and this is where big banks and monoline (broker-channel) lenders diverge sharply.

• Monoline / fair-penalty lenders typically compare your contract rate to their current rate for the remaining term. The math is close to the simple formula above and tends to produce a smaller, fairer penalty.
• Big banks often start from their inflated posted rate (a sticker rate almost no one actually pays), subtract the discount you originally received, and compare that to a posted rate for the remaining term. Because posted rates are artificially high, this method inflates the rate gap — and the penalty along with it.

The result is that two borrowers with identical mortgages can face wildly different penalties depending on whose contract they signed. How your lender defines the comparison rate is written into your mortgage agreement — read that clause before you assume anything.

A worked example

Consider a borrower with a $400,000 balance, three years (36 months) remaining on a five-year fixed term, and a contract rate of 5.00%. Since signing, fixed rates for a comparable term have fallen by about 1.00%. Compare the three possible penalty figures:

You pay the greater of three months' interest and the applicable IRD, so the monoline borrower owes roughly $12,000 while the big-bank borrower could owe closer to $30,000 on the same mortgage — driven almost entirely by the posted-rate comparison. Note the time effect too: if only three months remained instead of three years, the IRD would shrink toward the three-months-interest figure. These are illustrative figures only — your lender's exact method and rounding will differ, so always confirm the real number. You can sketch an estimate with our mortgage prepayment penalty calculator.

When each penalty applies: fixed vs variable

The penalty type follows your rate type:

• Variable-rate closed mortgage — almost always three months' interest. Modest and easy to predict, which is a quiet advantage if there's any chance you'll break early.
• Fixed-rate closed mortgage — the greater of three months' interest or the IRD. Early in the term, with rates lower than your contract rate, the IRD usually wins and can be very large.
• Open mortgage — no penalty at all, by design.

This is one of the practical trade-offs to weigh when you choose between fixed and variable: the rate isn't the only cost — the exit cost matters too.

Prepayment privileges that avoid penalties

Most closed mortgages include built-in privileges that let you pay down principal penalty-free. Used well, they reduce or even eliminate a penalty:

• Annual lump-sum prepayment — typically 10–20% of the original principal each year with no penalty.
• Payment increase — the option to raise your regular payment by a set percentage.
• Double-up payments — paying extra alongside a regular payment.

If you're about to break, using your annual lump-sum privilege first shrinks the balance the penalty is calculated on, which directly lowers the penalty. The mechanics of these calculations are covered in more depth in how prepayment penalties are calculated.

How to decide if breaking early still saves money

Breaking can absolutely be worth it — the question is whether the savings beat the penalty. Run a simple break-even:

1. Get the exact penalty from your lender (don't estimate for the final decision).
2. Calculate your interest savings over the remaining term at the new, lower rate versus your current rate.
3. Subtract the penalty and any switch costs (legal, appraisal, discharge fees) from those savings.

If the net is positive — and especially if you're also consolidating higher-interest debt or pulling out equity — breaking may make sense. If you're refinancing to access funds rather than chase a rate, weigh it inside the broader mortgage refinancing picture. If you're simply nearing the end of your term, waiting for renewal avoids the penalty entirely.

Porting and blending to avoid a penalty

You don't always have to break. Two options sidestep the penalty:

• Porting — if you're moving, you carry your existing rate and mortgage to the new property, avoiding the penalty. See porting your mortgage explained.
• Blend-and-extend — some lenders blend your current rate with a new one and extend the term, instead of charging a hard break penalty, letting you capture some rate benefit without paying the IRD up front.

Frequently asked questions

What is the interest rate differential (IRD)?

The IRD is a prepayment penalty on fixed-rate mortgages that approximates the interest your lender loses over the rest of your term when you break early. It's based on the gap between your rate and a comparison rate, your balance, and the months remaining — and it's the figure that makes fixed-mortgage penalties large.

Why is my fixed-mortgage penalty so much higher than three months' interest?

Because the IRD is larger, and you pay the greater of the two. The IRD grows when rates have fallen since you signed and when more term remains. Big banks also tend to use inflated posted rates in the comparison, which inflates the penalty further.

Do variable-rate mortgages have an IRD penalty?

Generally no. Variable closed mortgages are almost always charged three months' interest, which is small and predictable. The IRD is a fixed-rate feature.

Can I avoid the penalty entirely?

Sometimes. Wait until renewal (no penalty at term-end), port your mortgage if you're moving, ask about a blend-and-extend, or use your annual prepayment privileges to reduce the balance the penalty is based on.

Is breaking my mortgage worth the penalty?

It depends on the math. If your interest savings at the new rate, minus the penalty and switch costs, come out positive over the remaining term, breaking can save money — especially if you're also consolidating debt or accessing equity. Always run the break-even with your lender's exact penalty figure.

Thinking about breaking or refinancing? Ask Maya for a quick estimate of your penalty, or talk to an advisor — we'll pull your exact figure, run the break-even, and tell you whether breaking, porting, blending, or simply waiting for renewal puts you ahead.