How Canadian Mortgages Actually Work
Canadian mortgages have a few quirks that catch people off guard — and that most US-built calculators get wrong. Here are the essentials.
Term vs amortization: two different clocks
These get mixed up constantly:
- Amortization is how long it takes to pay the mortgage off completely — often 25 years.
- Term is how long your current interest rate is locked in — usually 1 to 5 years (5 is most common).
When your term ends, you don’t owe the whole thing — you renew the remaining balance at whatever interest rates exist then. So a 25-year mortgage with 5-year terms means you’ll renew about five times, each time facing new rates. That “balance at renewal” number is one of the most useful things to know, and the mortgage calculator shows it.
Semi-annual compounding (the Canadian quirk)
By law, Canadian fixed-rate mortgages compound interest twice a year (semi-annually), not monthly like in the US. The practical effect: your real cost is slightly lower than a naïve “rate ÷ 12” calculation suggests, and a US calculator will overstate your payment. (Variable-rate mortgages compound monthly.)
You don’t need to do this math yourself — just know that a proper Canadian calculator accounts for it.
The accelerated-payment trick
This is the single easiest way to save thousands. Your lender offers several payment frequencies:
- Monthly — 12 payments a year.
- Regular bi-weekly — your monthly amount spread across 26 payments (same yearly total).
- Accelerated bi-weekly — half your monthly payment, every two weeks.
Here’s the magic: there are 26 two-week periods in a year, so accelerated bi-weekly means you make the equivalent of 13 monthly payments instead of 12. That one extra payment a year goes straight to principal.
Here’s the same $500,000 mortgage at 4.5% over a 25-year amortization, paid different ways:
| Payment schedule | Payment | Total interest | Paid off in |
|---|---|---|---|
| Monthly | $2,767 / mo | $330,000 | 25 years |
| Regular bi-weekly | $1,277 / 2 wks | $329,000 | 25 years |
| Accelerated bi-weekly | $1,384 / 2 wks | $280,000 | 21.7 years |
| Accelerated weekly | $692 / wk | $280,000 | 21.7 years |
Just switching to accelerated bi-weekly saves about $50,000 in interest and pays the mortgage off ~3 years sooner — same mortgage, same rate, only the schedule changed. See it on your own numbers in the mortgage calculator.
Where your money actually goes
Early in a mortgage, most of each payment is interest, not principal — which is why the balance barely moves at first. As the balance shrinks, more of each payment chips away at principal, and it accelerates. The calculator’s principal-vs-interest split makes this visible.
Prepayments
Most Canadian mortgages let you prepay some amount each year (a lump sum and/or a payment increase) without penalty. Every prepayment goes entirely to principal, so it saves you all the future interest that principal would have cost. Even small, occasional prepayments add up.
The takeaway
- Know the difference between your term (rate lock) and amortization (payoff time).
- Expect to renew at unknown future rates — and check your balance at renewal.
- Use accelerated payments and prepayments to quietly save a fortune in interest.
Run your real numbers — including accelerated payments and your renewal balance — in the Canadian mortgage calculator.
This is general education, not financial advice. Confirm prepayment limits and terms with your specific lender.