Calculate Canadian mortgage payments including CMHC insurance and the OSFI B-20 stress test. Uses the Canadian semi-annual-compounding payment formula (every Canadian fixed-rate lender uses this). Computes GDS/TDS ratios so you can check whether you'd qualify under federal rules.
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Stress test qualification
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Monthly payment
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LTV
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Total loan
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Total interest
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CMHC insurance
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Stress test (OSFI B-20)
Qualifying rate
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Payment at qualifying rate
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GDS @ stress (max 39/35%)
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TDS @ stress (max 44/42%)
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Canadian-specific complexity
A Canadian mortgage isn't a US mortgage with different rates. Four things differ structurally:
Semi-annual compounding — fixed-rate mortgages must compound interest no more than twice a year by law, so the effective monthly rate is calculated differently. This makes Canadian payments slightly lower than equivalent US payments at the same nominal rate.
CMHC default insurance — required for any down payment under 20%, with premium added directly to the mortgage balance. Premium rates rise sharply with LTV.
OSFI stress test — banks must qualify you at contract + 2% or 5.25%, whichever is higher. This is what determines maximum borrowing power, not the contract rate.
Tiered minimum down payment — 5% on first $500k, 10% on $500k–$1.5M, 20% above. Federal rules.
Federally-regulated lenders (banks) must qualify you at the higher of (a) your contract rate + 2 percentage points, or (b) 5.25%. This is OSFI's B-20 minimum qualifying rate, designed to make sure you could still afford the mortgage if rates rose. At contract rates currently around 5%, most borrowers are stress-tested at contract + 2% = ~7%. The 5.25% floor only matters when contract rates fall below 3.25% — rare in 2026.
What's the minimum down payment in Canada?
Under federal rules: 5% on the first $500,000 of the purchase price, 10% on the portion from $500k to $1.5M, and 20% on anything above $1.5M. CMHC insurance is required for any down payment under 20%. Above $1.5M purchase price, CMHC insurance is not available — you must put down at least 20%.
How does CMHC insurance work?
When your down payment is under 20%, you must pay CMHC (or Sagen / Canada Guaranty) mortgage default insurance. The premium is calculated as a percentage of the loan amount and added to your mortgage balance — you pay it off over the life of the loan. Premium rates rise with LTV: 2.8% at 80-85% LTV, 3.1% at 85-90%, 4.0% at 90-95%. Above 95% LTV the loan is not insurable.
What are GDS and TDS ratios?
Gross Debt Service (GDS): monthly housing costs (stressed mortgage payment + property tax + heat + 50% of condo fees) divided by gross monthly income. Max 39% for insured mortgages, 35% for uninsured. Total Debt Service (TDS): GDS plus all other monthly debt payments (car loans, credit cards, lines of credit, student loans). Max 44% insured, 42% uninsured. Lenders use the stress-tested payment, not your contract payment, when computing these.
Why does Canadian mortgage math compound semi-annually?
The Interest Act of Canada (federal legislation) requires fixed-rate mortgage interest to be compounded no more than semi-annually. Your monthly payment is therefore not based on a simple annual_rate/12 — it uses the equivalent monthly rate of a semi-annual compound. Effective monthly rate = (1 + annual/2)^(1/6) − 1. This makes Canadian payments slightly lower than US-style monthly-compounded payments at the same nominal rate. Every Canadian fixed-rate lender uses this formula.
Can I get a 30-year amortization?
Yes for uninsured mortgages (20%+ down). For insured mortgages, the standard maximum is 25 years, but as of August 2024 first-time buyers and buyers of newly-built homes can get 30-year insured amortizations. Longer amortizations reduce monthly payments but increase total interest paid meaningfully.
What about provincial land transfer tax?
Every province charges land transfer tax on home purchases (some cities like Toronto and Montreal add municipal LTT). Rates vary widely — Ontario's tops out at 2%, BC's at 5% on luxury properties, Quebec at 2.5%. This calculator doesn't include LTT — budget separately, typically 1-3% of purchase price.