Mortgage Penalty Calculator

What the Mortgage Penalty Calculator does

This calculator estimates what it would cost to break your mortgage today, using both methods Canadian lenders actually use to calculate an interest rate differential — not just the one that produces the smaller, friendlier-looking number. Most bank websites show only their own method with no comparison, which makes it impossible to tell whether a quoted penalty is reasonable or inflated.

It shows three months' interest, the standard IRD method that monolines and most credit unions use, and the posted-rate IRD method that the big banks use, side by side. It then applies your unused prepayment privilege to show what the penalty would be on a reduced balance, and lists the practical ways to lower or avoid the charge entirely.

• Three months' interest, the floor penalty on any fixed-rate mortgage
• IRD under the standard method used by monolines and credit unions
• IRD under the posted-rate method used by most big banks
• The penalty after applying your unused annual prepayment privilege
• Discharge and admin fees, and the total cash cost to break

The key variables that move the answer — and how lenders treat them

Four inputs decide almost the entire result, and two of them are the ones borrowers usually cannot find on their own statement.

• Months remaining in your term — both three-months'-interest and IRD scale directly with this number, so a penalty falls fast as you approach renewal. Lenders calculate it from the exact discharge date, not the calendar month.
• Lender type — decides which IRD method applies. Big banks are contractually entitled to use the posted-rate method, which nets today's posted rate against the discount you received when you signed; monolines and most credit unions compare your contract rate directly against their current market rate, which is almost always the smaller comparison.
• Discount received at origination — the more discount you negotiated off the posted rate when you signed, the larger a posted-rate penalty becomes today. This is mechanical: subtracting a bigger discount from today's posted rate pushes the comparison rate down and widens the gap against your contract rate.
• Current comparison and posted rates — lenders use their own current rate sheet for the term closest to your months remaining, not a public benchmark. These numbers move with the market and are the ones most worth confirming directly with your lender before you rely on an estimate.

How mortgage penalties are actually calculated in Canada

Three months' interest is the simplest of the two formulas: your outstanding balance multiplied by your contract rate, divided by four. It applies on its own to every variable-rate mortgage at nearly every lender, and it is also the floor on fixed-rate penalties — you never pay less than this.

The interest rate differential compares your contract rate to a current comparison rate over your remaining months, and multiplies that gap by your balance. The standard method uses the lender's current posted or discounted rate for a term matching what you have left. The posted-rate method instead subtracts your original discount from today's posted rate before comparing, which mechanically produces a larger IRD whenever that original discount exceeds the current gap between posted and street rates — the usual situation, and the reason big-bank penalties are so often several multiples of a monoline equivalent on an identical balance and rate.

The final penalty on a fixed-rate mortgage is the greater of the two: three months' interest or the IRD calculated under whichever method your lender uses. A discharge or administration fee, typically a few hundred dollars, is added on top and is separate from the penalty itself.

• Three months' interest: balance × contract rate ÷ 4
• IRD, standard method: balance × (contract rate − current comparison rate) × months remaining ÷ 12
• IRD, posted-rate method: balance × (contract rate − (posted rate − original discount)) × months remaining ÷ 12
• Fixed-rate penalty: greater of three months' interest or IRD. Variable-rate penalty: three months' interest only

What you get from this calculator, and how a lender uses these numbers

A payout statement from your lender will land on a single number with no explanation of how it was built. Understanding which formula produced it — and whether a smaller number was available to you under a different method — is the difference between accepting a figure and being able to question it.

• Method that applies to you — tells you which formula to expect on your actual payout statement, based on your lender type and rate type
• The gap between the two IRD methods — quantifies exactly what switching lender types would have been worth, useful context even if you cannot change it after the fact
• Penalty after your privilege — a real, actionable number if your lender allows a privilege prepayment before a full discharge
• Total cost to break — the figure that actually belongs in a break-versus-stay or refinance decision, not the penalty alone

Using your results well

Use this number to sanity-check a payout statement, not to replace one. If your lender's quoted figure is materially higher than this estimate, ask specifically which method and which comparison rate they used, and request the calculation in writing — lenders are required to disclose the methodology on request.

This calculator deliberately stops at the penalty. It does not tell you whether breaking is worth it once the penalty is weighed against a lower rate over your remaining term — that comparison belongs on the break-versus-stay calculator, which takes this exact output as its starting point.

• Request an official payout statement before relying on any estimate, including this one
• Ask which IRD method applies to your file and which comparison rate was used
• Check whether your lender allows a privilege prepayment ahead of a full discharge
• Take this number to the break-versus-stay calculator before deciding anything

Related calculators