The Canadian mortgage stress test (officially OSFI Guideline B-20) has been law since January 2018, and it has a significant impact on what you can borrow. The stress test requires you to prove you can afford mortgage payments at a rate that's 2% higher than your actual rate or 5.25%, whichever is greater. Here's everything you need to know to navigate it.
How the Stress Test Works
When you apply for a mortgage in Canada, your lender must qualify you at the higher of: your contract rate + 2%, or 5.25%. That 5.25% floor is set by OSFI (the federal banking regulator) for uninsured mortgages at federally regulated lenders; insured mortgages face an equivalent federal qualifying rule. If your lender offers you a 5-year fixed rate of 5.0%, they must verify you can afford payments at 7.0%. This typically reduces your maximum borrowing power by 15-20%.
⚠️ Important Consideration
Example: Without a stress test, a household earning $120,000/year might qualify for $680,000. With the stress test at the qualifying rate, the same household qualifies for approximately $540,000, representing a $140,000 difference on the same income and same actual rate.
GDS and TDS Ratios: The Two Rules Lenders Apply
Lenders use two debt ratios to assess your mortgage application:
| Ratio | What It Measures | Maximum Allowed | Calculation |
|---|---|---|---|
| GDS (Gross Debt Service) | Housing costs only | 39% of gross income | Mortgage P+I + property tax + heating + 50% condo fee |
| TDS (Total Debt Service) | All debts combined | 44% of gross income | GDS + all other debt payments (car, student loan, credit card minimums) |
What the Numbers Look Like at Different Income Levels
| Gross Household Income | Qualifying Rate (stress test) | Max Mortgage (approx) | Assumed 5% Down, 25yr am |
|---|---|---|---|
| $80,000 | 7.0% | $360,000 | Home price: ~$379,000 |
| $100,000 | 7.0% | $450,000 | Home price: ~$473,000 |
| $130,000 | 7.0% | $585,000 | Home price: ~$616,000 |
| $160,000 | 7.0% | $720,000 | Home price: ~$758,000 |
| $200,000 | 7.0% | $900,000 | Home price: ~$947,000 |
Strategies to Qualify for More
- Pay down existing debt before applying: credit card balances and car loans reduce your TDS ratio
- Increase your down payment: a larger down payment reduces the mortgage amount needed
- Add a co-borrower - a spouse, partner, or family member's income can be added to the application
- Extend the amortization to 30 years: monthly payments are lower so you qualify for more (insured mortgages with less than 20% down are capped at 25 years, except that since December 15, 2024, first-time buyers and buyers of newly built homes can get up to 30 years)
- Choose a shorter amortization only if you can easily qualify, as the stress test uses your actual amortization payment
- Avoid applying for new credit in the 3-6 months before your mortgage application
- Talk to a mortgage broker: they access multiple lenders and may find better qualifying criteria
ℹ️ Key Note
Renewing? Since November 21, 2024, OSFI has exempted straight switches of uninsured mortgages from its stress test: if you move your existing mortgage to another federally regulated lender at renewal without increasing the loan amount or the remaining amortization, OSFI no longer requires the new lender to qualify you at the minimum qualifying rate (lenders still check that you can afford the payments). Borrowing more, extending the amortization, or refinancing brings the stress test back.
💡 Strategy Highlight
Our Mortgage Calculator's "Max Qualify" mode calculates your estimated maximum mortgage based on your household income, existing debts, and province using the current stress test rate. Use it to set your home buying budget before you start shopping.
