Why This Calculator Is Different From Most
Most mortgage calculators online use monthly compounding — which slightly overstates your payment. Canadian law requires semi-annual compounding on all residential mortgages, and that’s what this calculator uses. The result matches what your lender will show in a commitment letter.
If your down payment is under 20%, CMHC insurance is added automatically at the correct tier (4.00%, 3.10%, or 2.80%) and the Ontario PST on that premium is flagged separately. Property tax is estimated at Ontario’s average 0.85% mill rate — adjustable for your specific municipality.
What the B-20 Stress Test Means for Your Payment
Your monthly payment is based on your actual contract rate — not the stress test rate. But your maximum mortgage is calculated at the stress test rate (contract + 2%, minimum 5.25%). At today’s 4.79% rate, you qualify at 6.79%, which can reduce your maximum mortgage by $80,000–$120,000 compared to what you’d qualify for at contract rate alone.
Use the Maximum Mortgage Calculator to see what you qualify for, then come back here to confirm the payment fits your budget.
Ontario Mortgage Calculator — Common Questions
Mortgage Calculator FAQ — Ontario Rules Explained
Canadian semi-annual compounding, CMHC tiers, and the stress test confuse a lot of Ontario buyers. Here are the questions we see most often.
Yes — property tax is estimated at Ontario’s average mill rate of 0.85% of purchase price annually. Actual rates vary: Toronto ~0.66%, Vaughan ~0.78%, Brampton ~0.97%, Hamilton ~1.25%. Adjust the toggle to match your target municipality.
Two reasons. First, banks quote their posted rate (5.49%+) — broker rates are 40–80 basis points lower. Second, some bank calculators use simplified rounding rather than the exact Canadian semi-annual formula. This calculator matches your commitment letter.
On a $640,000 mortgage at 4.79%, 30-year amortization reduces your payment by approximately $310/month versus 25 years. The trade-off: significantly more total interest over the life of the mortgage. Available to first-time buyers on insured mortgages as of December 2024.
CMHC mortgage default insurance is required on all mortgages with less than 20% down in Canada. The premium (2.80%–4.00% of mortgage amount) is added to your mortgage balance — not paid upfront. Ontario also charges 8% PST on the premium, which is paid in cash at closing.
Still Have Questions?
Not seeing your exact situation here? Let’s take a look at your numbers and walk through your options step by step.
