Mortgage Affordability Calculator (Quebec, 2026)

The gross debt service (GDS) ratio compares your housing costs with your gross monthly income. It adds the mortgage payment (principal and interest, calculated at the qualifying rate), property taxes, heating and half of any condo fees. For CMHC-insured loans, GDS must not exceed 39%.

The total debt service (TDS) ratio adds all your other debt payments to those costs: car loan, student loan, support payments, credit card and line of credit payments. The limit is 44%. According to CMHC, an unsecured credit card or line of credit counts as 3% of the balance each month, even if you pay less. Whichever ratio is tighter sets your maximum payment.

Example: with an income of $100,000, monthly income is $8,333. At 39%, eligible housing costs are $3,250. If property taxes are $300 a month and heating is $100, $2,850 remains for principal and interest. If you also have a $600 car payment, TDS limits that amount to $2,667 instead.

Since 2018, federally regulated lenders must check that you could still pay your mortgage if rates went up. The Office of the Superintendent of Financial Institutions (OSFI) sets the minimum qualifying rate at the greater of two rates: the contract rate plus 2 percentage points, or 5.25%. CMHC applies the same rule to insured loans.

With a 4.5% rate, you must therefore qualify at 6.5%. The maximum payment allowed by the ratios is converted into a loan at that rate, which reduces the amount you can borrow. Your actual payment is calculated at the contract rate: the calculator shows both so you can see the safety margin. Provincially regulated credit unions and caisses are not covered by the OSFI guideline and apply their own criteria; for an insured loan, the CMHC rule applies regardless.

The minimum down payment is 5% of the first $500,000 and 10% of the portion between $500,000 and $1.5 million. From $1.5 million, insurance is no longer available and you need at least 20%. For a $600,000 home, the minimum is therefore $35,000.

If your down payment is under 20%, the loan must be insured. The premium is added to the loan: 2.80% if the loan-to-value ratio is 85% or less, 3.10% up to 90% and 4.00% up to 95%. A 0.20% surcharge applies to a 30-year amortization, available since December 15, 2024 to first-time buyers and buyers of a newly built home. In Quebec, the premium is also subject to the 9% tax on insurance premiums in 2026 (9.975% for premiums paid after December 31, 2026). That tax cannot be financed: it is paid in cash at the notary.

Qualifying for a loan does not mean the payment is comfortable. The ratios ignore childcare, groceries, retirement savings and home maintenance. Many advisers suggest keeping a margin below the maximum.

Also plan the cash needed for the transaction: the welcome tax (about $4,000 for a $400,000 home with the provincial brackets), notary fees, inspection, the tax on the CMHC premium and moving costs. Our welcome tax calculator and mortgage calculator help you complete that budget. And if you are saving for your down payment, compare the FHSA, the TFSA and the HBP with our dedicated tools.