Canadian Mortgage Calculator · Practical guide
Semi-Annual Compounding Mortgage Explained
Canadian law requires semi-annual compounding, which quietly makes your effective monthly rate a bit lower than you would expect.
At a glance
The short answer
Canadian mortgages compound twice a year, not monthly. A quoted 5% annual rate converts to an effective monthly rate of about 0.4124% — compared to 0.4167% if you simply divided by 12 as U.S. mortgages do. The difference is small each month but adds up over a long amortization.
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Enter your own values, then compare the result with the examples below.
Results
How the conversion works
The calculator applies the standard Canadian formula: monthly rate = (1 + annual/2)^(2/12) - 1. The nominal rate is first compounded semi-annually, then that effective annual rate is spread across twelve monthly payments. On a 5% rate the result is (1.025)^(1/6) - 1 = 0.4124%.
| Quoted Rate | Canadian Monthly Rate | Simple Rate / 12 (U.S.) |
|---|---|---|
| 4.0% | 0.3305% | 0.3333% |
| 5.0% | 0.4124% | 0.4167% |
| 6.0% | 0.4939% | 0.5000% |
Why it matters in dollars
On a $400,000 loan over 25 years at 5%, semi-annual compounding saves roughly $9 per month versus U.S.-style monthly compounding — over $2,600 across the full amortization. It is not dramatic, but it means Canadian payment quotes are never directly comparable to U.S. calculator results at the same headline rate.
Term versus amortization
Compounding is only half the Canadian puzzle. Your rate applies for a short term (commonly 5 years) while payments are spread over a longer amortization (25 or 30 years). When the term ends, you renew at the current market rate on the remaining balance, which can move your payment up or down significantly.
Frequently Asked Questions
Is semi-annual compounding better or worse for borrowers?
Slightly better. It produces a lower effective monthly rate than monthly compounding at the same quoted rate, so Canadian borrowers pay a touch less interest than the headline rate suggests.
Do all Canadian mortgages use semi-annual compounding?
Fixed-rate mortgages are required by law to compound semi-annually at most. This calculator applies that convention to every result.
Why does my U.S. calculator give a different payment for the same rate?
U.S. mortgages compound monthly, so a 5% rate becomes 0.4167% per month instead of 0.4124%. Use a Canada-specific calculator for Canadian loans.
Does the compounding affect variable rates too?
Variable-rate mortgages also use semi-annual compounding conventions, but the rate itself floats with the lender's prime rate, which moves your payment or amortization over time.