Canadian compounding in plain terms
Most Canadian residential mortgages compound interest semi-annually, even when you pay monthly or biweekly. That is different from many U.S. loans that compound monthly. Your payment schedule and the compounding convention both matter when you compare “extra” strategies.
Payoff Lab’s calculator converts the posted annual rate into the period rate used for Canadian semi-annual compounding, then simulates payments. Results are estimates for education — not a quote from your lender.
Why extra payments matter
Each payment is split between interest and principal. When you send extra dollars that apply to principal (and your mortgage allows it), you typically reduce the balance sooner. A smaller balance means less interest accrues over the remaining life of the loan, so payoff can arrive earlier.
Before you change anything, check your mortgage documents or ask your lender about:
- Prepayment privileges (annual % of original or outstanding principal, lump-sum windows)
- Whether “extra” can be added to regular payments or only as a separate principal payment
- Any fees, notice rules, or limits on increasing payment amount
Monthly vs biweekly vs accelerated biweekly
Canadian lenders commonly offer these payment frequencies. High-level differences:
- Monthly — twelve scheduled payments per year. Extra is often modeled as an amount added to each monthly payment.
- Biweekly — payment every two weeks. A common approach sets each biweekly amount so that the year’s total roughly matches twelve monthly payments (26 half-months ≈ one year of monthly totals), then any true “extra” is on top.
- Accelerated biweekly — often about half of the monthly payment, every two weeks. Because there are 26 half-payments in a year, you tend to pay the equivalent of roughly thirteen monthly payments over twelve months — a built-in acceleration even before voluntary extras.
Exact formulas and rounding vary by lender. Use the calculator to compare frequencies on your balance, rate, and amortization — do not rely on generic dollar examples.
Try it with your numbers
Enter your balance, rate, and amortization, then switch frequency and add an optional extra monthly amount. You’ll see scheduled payment, interest, and how extras may shorten the term — under Canadian semi-annual compounding.
Renewal season?
If your term is ending soon, a short checklist can help you gather documents and questions before you talk to your lender. Soft option: our Canadian mortgage renewal checklist on Gumroad (CAD $4.99, one-time download). Educational only.
More on timing windows: Mortgage renewal checklist Canada.
After the mortgage feels lighter
Extra payments first. When cash flow eventually frees up, the calculator page has an optional Amazon.ca “fun money” section — browsing only, with affiliate disclosure. Not a cue to pause the mortgage.