Extend Amortization Calculator

See how much a longer amortization lowers your payment, and what it adds in total interest and years of payments.

The trade-off in one line

Stretching the amortization spreads the same balance over more payments, so each payment shrinks, but interest is charged for more years. The Financial Consumer Agency of Canada warns that extending your amortization can add thousands or even tens of thousands of dollars in interest, so treat it as a tool for a tight budget rather than a default. Source: FCAC

Worked example

A $423,190 balance at 4.29% with 20 years left costs about $2,621 a month. Extending to 25 years drops the payment to about $2,293, saving roughly $328 a month, but total interest rises by about $58,900 over the life of the mortgage. Use the calculator for your own numbers.

When extending can make sense

• Your payment would otherwise rise beyond what your budget can carry.
• You plan to make prepayments when you can, so the longer amortization is a safety margin rather than the plan.
• You will use the monthly savings to pay off debt with a much higher interest rate.

Things to check first

• Not every lender allows an extension at renewal, and switching lenders with a longer amortization means you must re-qualify, including the stress test.
• Insured mortgages have maximum amortization limits.
• You can often shorten the amortization again at the next renewal or with prepayments. Model this with the prepayment calculator.

Frequently asked questions

Is extending the same as a longer term?

No. The term is how long your rate and contract last (often 5 years). The amortization is the total time to pay the mortgage off. This calculator changes the amortization only.

Reviewed October 2026 · How we build our calculators · Report an issue