Why Your Borrowing Capacity from the Bank Is Almost Never the Same as an Online Calculator’s Result

Thomas had run three different mortgage calculators before calling us. They all landed around the same place: roughly $450,000. His pre-approval came back at $365,000. He was sure something was wrong.

Nothing was. Online calculators generally estimate your capacity from your income and today's posted rate. Lenders have to qualify you at a higher rate than the one you'll actually pay, and they count your existing debts in a way most calculators don't.

Since 2021, federally regulated lenders must qualify you at whichever is higher: your contract rate plus 2%, or 5.25% (the benchmark rate set by the Office of the Superintendent of Financial Institutions). This is the minimum qualifying rate, or stress test. In practice, if your actual rate is 4.5%, you're assessed as if you were paying 6.5%, even though your real monthly payment will be calculated at the lower, actual rate.

The lender then calculates two ratios from the payment set at the qualifying rate. Gross Debt Service (GDS) compares your housing costs (mortgage payment at the qualifying rate, property tax, heating, and 50% of condo fees if applicable) to your gross income: the maximum generally sits around 39% for an insured mortgage and 35% for a conventional one. Total Debt Service (TDS) adds all your other debts, car loan, credit cards, lines of credit, student loans, into the calculation, with a maximum generally around 44% for an insured mortgage and 42% for a conventional one. These thresholds vary by lender, but they're the most commonly used benchmarks.

his income was more than enough for the amount he was targeting, but a $480-a-month car loan pushed him above the conventional TDS threshold. We ran two scenarios: paying down part of the car loan before applying, or accepting a lower mortgage amount. Thomas chose to pay down part of his car loan balance with savings he had set aside, which raised his approved capacity by close to $60,000.

Income is just one variable among others. Existing debts, the planned down payment (an insured and a conventional mortgage don't use the same thresholds), and the rate at the time all change the outcome. That's why two people with the same salary can get very different pre-approvals, and why an online calculator's number, which doesn't see any of these variables, is only a rough starting point.

An online calculator gives a general idea, not a reliable number. Our team can calculate your real capacity using your exact numbers, and flag whether adjusting an existing debt could make a difference before you even start looking. Let's talk it through together. As you probably already know, our services are free.