Mortgage Penalty and IRD Explained: Why Banks Charge More
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A mortgage penalty is what your lender charges when you pay off or break a closed mortgage before the end of its term. On a fixed rate, that charge is usually the greater of 3 months' interest or the interest rate differential, better known as the IRD. The IRD is where most of the surprises come from, because each lender picks the comparison rate it uses. This guide, part of our mortgage guides, explains both methods with the rules published by the Financial Consumer Agency of Canada (FCAC), checked on October 18, 2026.
You will also see one mortgage run through two lenders' formulas, with a penalty more than twice as high at one of them.
How a mortgage penalty works
You trigger a penalty when you repay more than your prepayment privileges allow before the term ends. That happens when you sell without porting the loan, refinance to get a lower rate or more cash, or move to another lender mid-term. An open mortgage lets you prepay without a penalty, but it usually carries a higher rate.
On a closed fixed-rate mortgage, the FCAC says the penalty is usually the higher of two amounts:
- 3 months' interest: three months of interest on what you still owe.
- Interest rate differential (IRD): the interest the lender loses because today's rates are lower than yours.
The FCAC adds that lenders usually use the IRD when your rate is higher than the current rate and you signed your contract less than 5 years ago. On a variable-rate mortgage, lenders such as RBC and First National charge 3 months' interest only.
Three months' interest
This part is simple. Multiply what you owe by your rate, then divide by 4. On a $400,000 balance at 4.99%, 3 months' interest is $4,990.
Because it depends only on your balance and your rate, this amount is easy to predict. It is also the floor: on a fixed rate, you never pay less than this when you break.
The interest rate differential
The IRD compares two rates: the rate in your contract and a current rate for a term close to the time you have left. The difference is applied to your balance for the months remaining. If rates have dropped since you signed, the gap is positive and the IRD can be large.
The FCAC gives this example. With a $200,000 balance at 6%, 36 months left, and a comparison rate of 4%, 3 months' interest is about $3,000, while the IRD is about $12,000. The lender charges the higher amount.
Posted rate vs discounted rate
Here is the detail that moves penalties by thousands of dollars. Lenders advertise posted rates, but most borrowers sign at a lower, discounted rate. What matters is which rate the lender uses as the comparison in the IRD.
Big banks often start from their posted rate. TD describes its comparison rate as the posted rate for a similar mortgage, minus any rate discount you received. RBC uses its posted rate for a term similar to the time remaining, less your rate reduction. If the discount you get today on a short term is larger than the one you got at signing, the comparison rate ends up low and the IRD goes up.
The gap between posted and special rates is real. On October 18, 2026, RBC's rate page showed:
- 3-year closed fixed: 6.250% posted, 4.990% special offer.
- 5-year closed fixed: 6.190% posted, 5.140% special offer.
How monoline lenders calculate it
Many monoline lenders, which only offer mortgages and sell through brokers, use the rate they actually offer today. First National defines the IRD as the difference between your rate and its current rate on a replacement mortgage for the time left in your term. Because that comparison rate is a real market rate, the gap with your rate tends to be smaller. Our guide to monoline lenders in Canada covers how these lenders work.
Methods differ within each group too, so read your own contract. Federally regulated lenders must explain how they calculate the penalty and say where you can find the comparison rate.
Worked example: one mortgage, two methods
Take a $400,000 balance at a fixed rate of 4.99%, with 36 months left on a 5-year term. The numbers below are hypothetical and use the simplified formula: balance × rate gap × months remaining ÷ 12.
- Lender A, posted-rate method: you got a 1.50% discount at signing, and today's posted 3-year rate is 5.49%, so the comparison rate is 3.99%.
- Lender B, current-rate method: today's actual 3-year rate is 4.69%.
| Item | Lender A: posted rate minus discount | Lender B: current rate |
|---|---|---|
| 3 months' interest | $4,990 | $4,990 |
| Comparison rate | 3.99% (5.49% - 1.50%) | 4.69% |
| Rate gap with your 4.99% | 1.00 point | 0.30 point |
| IRD (gap x balance x 36 / 12) | $12,000 | $3,600 |
| Penalty charged (greater amount) | $12,000 | $4,990 |
At Lender A, the IRD of $12,000 beats 3 months' interest, so you pay $12,000. At Lender B, the IRD is only $3,600, so you pay the floor of $4,990. Same balance, same contract rate, a gap of $7,010.
Real calculations are a bit lower than this shortcut. RBC notes that its IRD uses present value and accounts for the balance declining at each payment, two factors that reduce the amount. The order of magnitude still holds.
Is breaking your mortgage worth it?
Compare the penalty with what you save. In our example, suppose a new lender offers a 3-year rate of 4.09%. On $400,000, a 0.90% drop saves about $300 a month in interest at first, or roughly $10,800 over 36 months. That is a rough estimate: savings shrink a little as the balance falls.
With Lender A's $12,000 penalty, breaking loses money before legal and discharge costs. With Lender B's $4,990 penalty, it saves about $5,800. Run your own scenario with our mortgage refinance calculator and read our guide to refinancing a mortgage in Canada.
If your renewal is close, compare with staying put. Our mortgage renewal calculator shows your payment at a new rate, and our guide to early mortgage renewal explains when renewing ahead of time can avoid a penalty.
How to reduce or avoid the penalty
The FCAC suggests several ways to lower the bill.
- Use your prepayment privileges every year: each lump sum or payment increase lowers the balance on which a future penalty is calculated.
- Make a lump-sum prepayment before you break: within your annual limit, it reduces the amount the penalty applies to.
- Wait for the end of your term: at maturity, you can pay off or move your mortgage without a prepayment penalty.
- Port your mortgage: if you buy another home, ask your lender whether you can take your rate and conditions with you.
- Shop around before you sign: compare how each lender calculates the IRD, not only the rate.
Other costs when you break
The penalty is rarely the only charge. Ask your lender for a written payout statement, which lists the exact penalty, your balance, and any other amounts due. Under the federal code of conduct on prepayment information, your lender must also tell you about any other amounts you have to pay when you prepay, and how they are calculated.
A new lender may also bring its own costs, such as legal and appraisal fees. Some lenders cover part of them to win your business, so ask before you sign.
Questions to ask before you sign
The best time to manage a penalty is before you take the mortgage. Ask each lender:
- Which comparison rate do you use for the IRD: posted rate minus discount, or your current rate?
- What are my prepayment privileges: how much can I prepay each year, and how?
- Is the mortgage portable: can I move it to my next home, and on what conditions?
- Is there any other charge on prepayment, such as a clawback of a cash-back amount?
A mortgage broker can compare these terms across several lenders at once.
Conclusion
On a fixed-rate mortgage, you pay the greater of 3 months' interest or the IRD, and the IRD depends on the comparison rate your lender picks. Lenders that start from posted rates can charge far more than those that use their real current rate. Before you break, get a written payout statement, use your prepayment privileges, and compare the penalty with what you would really save. Before you sign, ask how the IRD is calculated.
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Frequently asked questions about mortgage penalties
How is a mortgage penalty calculated in Canada?
On a closed fixed-rate mortgage, the penalty is usually the greater of 3 months' interest on your balance or the interest rate differential (IRD). On a variable-rate mortgage, it is usually 3 months' interest. The exact method is in your contract and varies from one lender to another. Our mortgage guides explain each step of the process.
What is the IRD on a mortgage?
The interest rate differential compares your contract rate with a current rate for a term close to the time left on your mortgage. The gap is applied to your balance for the remaining months. It grows when rates have dropped since you signed. Compare lenders' methods in our guide to monoline lenders in Canada.
Why do big banks charge higher penalties?
Many big banks calculate the IRD from their posted rate minus the discount you received at signing. When today's discount on a short term is larger than yours was, the comparison rate is low and the IRD rises. Lenders that use their real current rate usually produce a smaller gap. A mortgage broker can explain how each lender calculates it.
Does Ratesopedia have a mortgage penalty calculator?
No. Your lender is the right source, because only it knows the comparison rate and discount in your file. Federally regulated lenders must post prepayment calculators on their websites, and you can ask for a written payout statement. To compare the savings with a new rate, use our mortgage refinance calculator.
Can I avoid a penalty when I sell my home?
Often, yes. If your mortgage is portable, you can move your rate and conditions to your next home and avoid breaking the contract. You can also use your prepayment privileges or time the sale with the end of your term. Check our early mortgage renewal guide if your term ends soon.
Is the penalty capped after 5 years?
For a mortgage with a term longer than 5 years, section 10 of the federal Interest Act lets an individual repay after 5 years with a maximum of 3 months' extra interest. This rule does not apply to mortgages given by corporations. If you consider a 7- or 10-year term, keep it in mind, and compare current rates on our 5-year fixed mortgage rates page.
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