Mortgage Stress Test Calculator

What the Mortgage Stress Test Calculator does

The federal stress test is the single most misunderstood rule in Canadian mortgage lending: you qualify at one rate and pay a different, lower one. This calculator runs the actual test — computing your qualifying rate, the payment it produces, and whether your income and debts clear the GDS and TDS limits at that higher payment — and puts your real payment right beside it so the gap is visible, not abstract.

It also covers the exemption question that trips up almost every renewing borrower: whether switching lenders, staying put, refinancing or buying changes whether the test even applies to you.

• Your qualifying rate, and the payment it produces on your mortgage amount
• A clear pass or fail against the 39% GDS and 44% TDS limits
• Your actual payment shown side by side with your qualifying payment
• If you fail: the maximum price that would pass, and the income needed at your current price
• Whether your transaction type may be exempt from re-testing, and the credit union alternative

The key variables that move the answer — and how lenders treat them

The stress test result is driven by a small set of inputs, and each one interacts with the test differently than it interacts with your actual payment.

• Contract rate — sets your actual payment, but the qualifying rate is derived from it by adding 2 percentage points. At today's typical rates the 5.25% benchmark rarely binds; the add-on almost always does.
• Down payment — decides whether the mortgage is insured, which changes the mortgage amount through the capitalised premium, but does not exempt anyone from the stress test itself. Every mortgage in Canada, insured or not, is stress tested.
• Amortization — a longer amortization lowers the qualifying payment along with the actual one, which is one of the few levers directly within a borrower's control when a file is failing.
• Transaction type — this is where lenders diverge from the general rule. A straight switch of an existing, uninsured mortgage to a new federally regulated lender at renewal may be exempt from re-testing, and staying with your existing lender at renewal has historically never required requalification, but a purchase or a refinance is always tested.
• Lender type — provincially regulated credit unions are generally not bound by the federal OSFI B-20 stress test, though they may apply their own qualifying standards. This is a genuine structural reason a borrower can fail at a bank and pass at a credit union.

How this is actually calculated in Canada

The qualifying rate is the greater of your contract rate plus 2.00 percentage points, or a fixed benchmark floor — currently 5.25%. That rate, not your contract rate, is used to compute the payment that feeds into your GDS and TDS ratios.

The qualifying payment is calculated the same way as any Canadian mortgage payment — using the periodic rate formula with semi-annual compounding for a fixed rate — but substituting the qualifying rate for the contract rate: i_q = (1 + rate_q ÷ 2)^(2 ÷ 12) − 1, payment_q = P × i_q ÷ (1 − (1 + i_q)^−N). That qualifying payment is then run through the same GDS/TDS calculation used everywhere else on this site.

When a file fails, the useful next question is what would pass. The maximum price that would pass is solved by testing candidate prices against the ratio limits at the qualifying rate, holding the down payment fixed; the income needed at the current price is solved directly from the ratio formulas, taking the higher of the income required to satisfy GDS alone and the income required to satisfy TDS alongside existing debts.

• Qualifying rate = MAX(contract rate + 2.00%, 5.25%)
• Qualifying payment: same formula as any Canadian mortgage payment, using the qualifying rate
• Pass/fail: qualifying payment run through GDS ≤ 39% and TDS ≤ 44%
• If failing: max price solved by bisection; income needed solved directly from the ratio limits

What you get, and how lenders use these numbers to qualify you

Every output here is the exact figure an underwriter checks — this is not an approximation of the stress test, it is the stress test.

• Qualifying rate — the number lenders substitute for your contract rate before running any ratio. It is disclosed on every rate quote but rarely explained.
• Pass/fail — the binary gate. A fail here means the file does not clear as currently structured, regardless of how attractive the contract rate is.
• Gap between actual and qualifying payment — this gap exists specifically as a buffer against future rate increases; lenders are testing whether you could absorb higher rates without becoming unable to pay.
• Maximum price that would pass — tells you exactly how much price flexibility closes the gap, which is often more useful than the pass/fail badge alone.
• Exemption flag — matters most at renewal, where a straight switch of an uninsured mortgage may not require the test at all, changing which lenders are realistically available to you.

Using your results well

If you are failing, run the calculator again with a longer amortization and again with a lower target price to see which lever closes the gap faster for your specific numbers. The maximum-price and income-needed figures above are calculated directly from your inputs, so they reflect your actual situation rather than a generic rule of thumb.

What this calculator deliberately does not do is check every lender's specific overlay or confirm exemption eligibility for your exact circumstances — exemption rules have changed before, differ by lender, and are worth confirming directly rather than assuming from a general description. It also cannot tell you whether a provincially regulated credit union's own qualifying standards would let you pass where a federally regulated bank would not; that comparison is exactly what a broker is positioned to run.

• If failing, compare a longer amortization against a lower target price to see which closes the gap faster
• Check the exemption flag carefully at renewal — it can change which lenders are realistically in play
• Ask specifically about credit unions if you are close to the line — they are not bound by the federal test
• Treat the maximum-price figure as a ceiling to shop under, not a target to spend up to
• Confirm exemption and qualifying-rule details directly before relying on them — this area changes

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