Rule

How do three months’ interest and the interest-rate differential affect my mortgage penalty?

Short answer

Many fixed closed mortgages charge the higher of three months’ interest or an interest-rate differential, while many variable closed mortgages use three months’ interest. The exact formula, comparison rate and discounts come from the contract and lender disclosure.

The client concern behind the question

Two clients with the same balance and months remaining receive very different penalties. One assumes the lender made a mistake because an online calculator showed a much smaller number.

What the verified rule or guidance says

FCAC describes both common methods and tells borrowers to ask the lender for the actual amount and calculation. The IRD estimates the lender’s interest loss, but lenders may use different comparison rates and contractual methods.

What it does not guarantee

A calculator is an estimate, not a payout statement. Posted-rate discounts, term remaining, prepayments, cashback, administration charges and the payout date can change the result. MIC and private commitments may use different formulas or minimum-interest clauses.

A practical Ontario example

Illustration only: A borrower’s discounted five-year fixed mortgage has two years remaining. The contract compares the mortgage rate with a selected two-year rate. A large rate gap produces an IRD far above three months’ interest, changing whether refinancing now creates any real saving.

Practical steps to consider

Request the calculation in writing and ask which comparison rate and balance were used. Run a break-even analysis that includes penalty, fees, new rate, remaining term and planned sale date. A lower rate is useful only when the savings survive the exit costs.

Questions to ask before deciding

  • Which statement is law or regulator guidance, and which part is the lender’s own policy?
  • What are the complete costs today, at renewal and at the expected exit?
  • What documents, dates or property facts could change the answer?
  • Would an A, alternative/B, MIC or private lender view the verified file differently?
  • What is the backup plan if the preferred route is declined or delayed?

Rajiv’s broker perspective

A useful answer must solve the client’s real concern, not repeat a definition. I would verify the documents and timeline, separate regulator requirements from lender policy, then compare the available routes in dollars. A conventional A lender may offer the lowest cost when the file fits. An alternative/B lender may use a broader income or credit approach. A MIC or private mortgage may provide short-term flexibility, but fees, interest, term and the exit must be clear. The right recommendation is the one the client can carry and exit safely.

Related: Mortgage declined? Start here · Mortgage Knowledge Centre · Updates & Rules Centre

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Sources and context

Read the primary source

Source checked
2026-09-08
Effective
2026-09-08
Next review
2026-12-08
Assumptions and limitations
The result depends on the current law or guidance, actual contract and disclosure, verified borrower and property facts, lender type, lender policy and transaction date.

Source checks are snapshots, not a guarantee that rules have remained unchanged. Individual circumstances and lender policies vary.

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