With interest rates declining in 2026, many Quebec homeowners wonder whether it’s worth breaking their mortgage to lock in a better rate. But beware: the prepayment penalty can be costly. If you’re considering a mortgage refinance, understanding these calculations is essential.
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Calculate my borrowing capacity📈 The Two Penalty Formulas
For a fixed-rate mortgage, the bank calculates two penalties and charges the higher amount:
1. Three-Month Interest Penalty
Remaining balance × Contract rate × 3 ÷ 12
Simple formula, generally the more favourable outcome for the borrower.
2. Interest Rate Differential (IRD)
Balance × (Rate gap) × Months remaining ÷ 12
Rate gap = your contract rate − lender’s current rate for the remaining term. Often much more expensive.
⚠️ Important: The bank always charges whichever amount is higher. This is why the IRD is dreaded when rates drop significantly.
🧮 Concrete Calculation on $400,000
Let’s take a realistic 2026 scenario: $400,000 mortgage at 4.5%, 5-year term with 3 years remaining, current rate 3.69%.
Scenario Data
• Remaining balance: $400,000
• Contract rate: 4.50%
• Lender’s current rate (3-year): 3.69%
• Months remaining in term: 36 months
3-Month Interest Penalty
$400,000 × 4.50% × 3 ÷ 12 = $4,500
IRD Penalty (Differential)
Rate gap = 4.50% − 3.69% = 0.81%
$400,000 × 0.81% × 36 ÷ 12 = $9,720
Result: The bank will charge the IRD penalty of $9,720 (the higher amount), more than double the 3-month penalty ($4,500). The $5,220 difference illustrates the major impact of IRD when rates drop. Before deciding, calculate whether the interest savings over 36 months at the new rate exceed this penalty.
💡 When to Break Your Mortgage in 2026
Large rate gap (> 1%)
If you’re paying 5% and current rates are 3.69%, the savings may exceed the penalty on a large balance.
Little time remaining in term
The shorter the remaining duration, the lower the IRD penalty (fewer months in the formula).
Property sale
When selling, the penalty is unavoidable unless you port the mortgage to your new property.
Need to refinance
Refinancing to consolidate high-interest debt may justify the penalty cost.
Also see our guide on mortgage renewal in 2026 to explore all your options.
✅ How to Avoid or Reduce the Penalty
Prepayment Privileges
Most lenders allow 10–20% of the principal to be repaid annually without penalty. Maximize these payments before breaking.
Mortgage Portability
Some lenders allow you to transfer your mortgage to a new property without penalty.
Negotiation with Lender
A mortgage broker can negotiate a penalty reduction or a “blend-and-extend” that mixes your old and new rates.
💳 Working with a Mortgage Broker
A mortgage broker compares offers from multiple lenders and can help you determine whether breaking your mortgage is truly worthwhile. They calculate the exact penalty, negotiate terms, and guide you toward the best solution: early renewal, refinancing, or waiting until the end of your term.
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