Every federally regulated lender in Canada must qualify you at the greater of your contract rate + 2% or 5.25% — not the rate you'll actually pay. This is OSFI's B-20 stress test, and it decides how much mortgage you can carry. Here's exactly how it works in Ontario in 2026, who it applies to, and how to pass it.
What the stress test is — and why it exists
The mortgage stress test is a federal qualifying rule introduced by OSFI (the Office of the Superintendent of Financial Institutions) under guideline B-20. It requires every federally regulated lender to confirm you could still afford your mortgage payment if rates were meaningfully higher than the rate you're being offered.
Mechanically: lenders qualify you at the greater of your contract rate + 2% or a 5.25% floor. The point isn't to change your payment — it's a stress buffer that protects both you and the financial system from payment shock when mortgages renew at higher rates.
The stress test math, with worked examples
Take your contract rate, add 2%, and compare to 5.25%. The higher number is your qualifying rate. In 2026, with most rates above 3.25%, the contract-plus-2% figure is almost always the binding one.
| Your contract rate | Contract + 2% | 5.25% floor | Qualifying rate used |
|---|---|---|---|
| 3.04% | 5.04% | 5.25% | 5.25% (floor wins) |
| 3.99% | 5.99% | 5.25% | 5.99% |
| 4.39% | 6.39% | 5.25% | 6.39% |
| 4.79% | 6.79% | 5.25% | 6.79% |
| 5.49% | 7.49% | 5.25% | 7.49% |
How the stress test feeds your GDS and TDS ratios
The stress test rate isn't a standalone hurdle — it's the interest rate plugged into your debt-service ratios. Lenders run two:
- GDS (Gross Debt Service) — your housing costs (mortgage payment at the stress-test rate, property tax, heat, plus half of any condo fees) divided by gross income. Generally must stay under ~39%.
- TDS (Total Debt Service) — GDS plus all your other debt payments (car loans, lines of credit, credit cards, support payments). Generally must stay under ~44%.
Who the stress test applies to — and who's exempt
The test applies to all federally regulated lenders: the Big-6 banks and national monoline lenders. It applies to purchases, refinances, and to switches to a new federally regulated lender.
| Scenario | Stress test applies? |
|---|---|
| Buying with a bank or monoline | Yes |
| Refinancing with any federally regulated lender | Yes |
| Switching to a NEW lender at renewal | Yes |
| Renewing with your EXISTING lender | No (re-qualification not required) |
| Provincial credit union (Ontario) | Often no — not bound by OSFI B-20 |
| Private mortgage | No — equity-based lending |
The renewal trap — and how to avoid it
Here's the catch that costs Ontario homeowners real money. If you renew with your current lender, you don't have to re-pass the stress test — but your lender knows that, so their renewal offer often isn't their sharpest rate. If you want to switch to a cheaper lender, that new lender must stress-test you, and on a tight file you might not pass.
The result: borrowers feel locked in and sign a mediocre renewal. A broker's job is to tell you in advance whether you'd pass a switch, and if so, capture the better rate. With Canada's 2025–2026 renewal wave bringing millions of mortgages up for renewal at higher rates, this matters more than ever. See our mortgage renewal guidance.
How to pass the stress test
- Lower your other debt. Clearing a car loan or credit-card balance cuts your TDS and directly raises your maximum mortgage.
- Add a co-applicant. A spouse or co-signer's income is added to the qualifying calculation.
- Increase your down payment. A smaller mortgage is easier to carry at the stress-test rate.
- Extend the amortization. A 30-year amortization (now available to first-time buyers and on new builds under 2024 rules) lowers the qualifying payment.
- Consider a credit union. Provincial credit unions may qualify you at the contract rate, not the stress-test rate.
- Talk to a broker first. We model your stress-tested numbers across multiple lenders before you write an offer — so there are no surprises in underwriting.
Frequently asked questions
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