How this calculator works
Refinancing swaps your existing mortgage for a new one — with your current lender or a new one — usually on your existing outstanding balance (or higher, if accessing home equity). The calculator works out your monthly payment on both the current and new deal, then compares them:
Monthly saving = current monthly payment − new monthly payment
If the new deal has fees — appraisal, legal, discharge, and/or a prepayment penalty for breaking your current term early — those fees eat into your saving before you're better off overall. The calculator finds yourbreak-even month (fees divided by the monthly saving, rounded up) and a lifetime saving figure over the shorter of your two remaining amortization periods, after fees. If the new deal doesn't lower your payment, there's no break-even point to find, and the calculator says so clearly.
Worked example
Say you have $350,000 outstanding, currently on a 6% rate with 22 years remaining. You're offered a new deal at 4.8% over a fresh 25-year amortization, with $1,500 in fees. The new deal noticeably lowers your monthly payment, and that saving typically recoups a fee of this size within a matter of months — with a substantial lifetime saving over the comparison term once fees are subtracted. Bear in mind part of any saving reflects stretching the loan back to a fresh 25-year amortization rather than the 22 years remaining — worth weighing alongside the monthly saving.
What affects your result
- The rate gap — the difference between your current and new rate is the biggest driver of your monthly saving.
- New deal fees, including any prepayment penalty — a lower rate with a large IRD penalty for breaking your term early can take much longer to break even than waiting until your term ends.
- Amortization changes — resetting to a longer amortization lowers the monthly payment further but increases total interest paid over the life of the loan.
- Fixed vs variable rate type — remember that fixed-rate mortgages compound semi-annually by law, while variable-rate mortgages compound monthly, at the identical quoted rate.
A note on accuracy
This calculator compares principal-and-interest payments only, using unrounded figures internally with rounding applied solely for display. It does not automatically calculate an Interest Rate Differential (IRD) penalty for breaking your current term — get an exact payout quote from your current lender and add it to the new deal fees field if applicable. For general guidance on refinancing, see Financial Consumer Agency of Canada.