Mortgage Stress Test: How It Works and How to Pass

The Qualifying Rate: The Core Rule

Example: If your lender offers 4.5%, you must qualify at 6.5% (4.5 + 2 > 5.25). If rates drop and you're offered 2.8%, you qualify at 5.25% (2.8 + 2 = 4.8 < 5.25, so the floor applies). Either way, you're qualifying significantly above your actual payment.

GDS and TDS Ratios Explained

Lenders use two ratios to test affordability at the qualifying rate. Both are calculated against gross (pre-tax) income.

Strategies to Qualify for More Mortgage

Frequently Asked Questions

The renewal exemption that changed everything

For years the stress test created a trap at renewal. A borrower who qualified in 2019 could fail the test in 2024 — through no change in their own circumstances — which meant they could not move to a competing lender. Their existing lender knew it, and had little reason to offer a competitive rate.

Since late 2024, borrowers renewing an insured mortgage can switch lenders without re-qualifying under the stress test, provided the loan amount and amortisation are not increased. If you are renewing an insured mortgage, shop it — and say explicitly that you are aware you can switch without re-qualifying. It is rarely volunteered, and the rate difference over a five-year term is frequently worth thousands.

Why a zero-balance credit line can cost you $100,000 of approval

The TDS ratio counts your available revolving credit, not your balance. A $30,000 line of credit you never touch is still assessed as a monthly payment, because you could draw on it tomorrow.

The same logic applies to credit card limits. Someone with three cards totalling $40,000 in limits carries an assumed monthly obligation even at a zero balance. Closing unused credit before you apply can raise your approval more than a raise would — and it is free. Do it at least a month ahead so the change reaches your credit file.

Uninsured mortgages are tested too

A persistent myth holds that 20% down avoids the stress test. It does not. B-20 applies to all mortgages at federally regulated lenders, insured or not. What 20% down avoids is default insurance, which is a different thing entirely.

There is a counterintuitive consequence worth knowing: insured mortgages often carry lower interest rates than uninsured ones, because the lender's risk is covered. Putting down exactly 20% can therefore mean a slightly higher rate than putting down 19.99% and paying the premium. It is not always the better deal — run both.

What the test does not measure

GDS and TDS use gross income — before income tax, CPP and EI. A household approved at the 39% GDS limit may be committing well over half its actual take-home pay to housing. The lender's ratio is a solvency test, not a budget.

It also ignores childcare, which for a family with two young children can exceed the mortgage payment; RRSP and pension contributions; and the maintenance reserve every homeowner needs. Run your approval figure through the paycheque calculator and check it against net income before treating it as a budget. Qualifying for an amount is not the same as it being affordable, and the stress test was never designed to answer the second question.

Frequently Asked Questions