Canadian Mortgage IRD Penalty Calculator

Canadian IRD (Interest Rate Differential) penalties are calculated as: outstanding balance × (contract rate − current posted rate for remaining term) × remaining months/12. The critical variable is which rate the lender uses for comparison — most Big Six banks use the original posted rate at origination vs. today's posted rate, which is deliberately unfavorable to the borrower.

Canada's Big Six banks calculate IRD using the posted rate at origination (typically 5.5–7%+) rather than the actual contract rate you received. Because the posted rate has historically been 2–3% above the discounted contract rate, the IRD calculation produces a larger penalty than a simple contract-rate differential would suggest. Credit unions and some monoline lenders use simpler 3-month-interest calculations instead.

Most Canadian lenders charge the greater of: (1) 3 months' interest on the outstanding balance at your contract rate, or (2) the IRD penalty. In a rising rate environment where current rates exceed your contract rate, the 3-month interest floor applies. In a falling rate environment, the IRD typically exceeds 3 months' interest.

Breaking a mortgage early is worth it when the interest savings over the remaining term exceed the total penalty cost. Divide the penalty by the monthly savings from the new rate to find the break-even in months. If you plan to stay in the property beyond that break-even, breaking early likely makes sense financially.

IRD penalties are contractually defined and difficult to negotiate directly. However, some lenders offer mortgage porting (transferring the mortgage to a new property) which avoids the penalty. Others offer blend-and-extend options that avoid the penalty while adjusting the rate. Ask your lender about these alternatives before paying the IRD.