If you have applied for a mortgage in Canada since 2018, you have encountered the stress test. Many buyers are surprised by it, because they are approved for less than they expected, even when they can easily afford the monthly payment at the advertised rate. This guide explains exactly how the test works, why it exists, and how to calculate whether you will pass it.
What the stress test is
The stress test is a rule from the Office of the Superintendent of Financial Institutions (OSFI), known as Guideline B-20. It applies to federally regulated lenders, which covers most major banks and many other lenders in Canada.
The rule is simple to state: when a lender checks whether you can afford a mortgage, it must test you at a higher interest rate than the one you will actually pay. Specifically, you must qualify at the higher of:
- Your actual mortgage contract rate plus 2%, or
- The Bank of Canada benchmark rate, published weekly as the “conventional mortgage rate.”
For example, if your contract rate is 5.25%, the stress test rate is 7.25% (5.25% + 2%). If the benchmark rate happens to be higher than that, the benchmark rate applies instead. In recent years the benchmark rate has been in the range of roughly 5.25% to 5.50%, so for most borrowers the “contract rate plus 2%” figure is the one that applies.
You will actually pay the contract rate, not the stress test rate. The higher rate is only used for the qualification check. But that check determines how much you can borrow.
Why the stress test exists
The stress test was introduced after a period of rapidly rising house prices and growing household debt in Canada. Regulators were concerned that borrowers who could afford payments at very low rates might struggle if rates rose.
The logic is straightforward. Interest rates change. If you borrow the maximum you can afford at 3%, and rates rise to 5% when you renew in five years, your payment jumps significantly. The stress test forces lenders to check whether you could still afford the mortgage if rates were 2% higher than today.
This is not a hypothetical concern. Between 2022 and 2023, Canadian mortgage rates rose by more than 3 percentage points in about a year. Borrowers who had been stress-tested were in a better position than those who had borrowed at their absolute limit without any buffer.
Critics argue the test locks some buyers, especially first-time buyers, out of the market. Supporters argue it prevents defaults and protects both borrowers and the financial system. Regardless of the debate, the rule is in force, and you need to plan around it.
How the test affects how much you can borrow
The stress test affects your borrowing power through two ratios: GDS and TDS.
Gross Debt Service (GDS) ratio is your housing costs divided by your gross income. Housing costs include mortgage principal and interest, property taxes, heating, and 50% of condo fees if applicable. Lenders generally want GDS at or below 39%.
Total Debt Service (TDS) ratio is all your debt payments divided by your gross income. This includes housing costs plus car loans, credit card minimum payments, lines of credit, student loans, and any other debts. Lenders generally want TDS at or below 44%.
The stress test enters the calculation because the mortgage payment used in GDS and TDS is calculated at the stress test rate, not your contract rate.
Here is a concrete example. Suppose your household income is $120,000 per year, or $10,000 per month. You have no other debts. You want to buy a home with a $500,000 mortgage at 5.25% with 25-year amortization.
At the contract rate of 5.25%, the monthly mortgage payment is about $2,972. Your GDS would be $2,972 plus property taxes and heating, divided by $10,000. If taxes and heating are $500 per month, GDS is ($2,972 + $500) / $10,000 = 34.7%. That passes the 39% limit.
At the stress test rate of 7.25%, the monthly payment is about $3,566. GDS becomes ($3,566 + $500) / $10,000 = 40.7%. That fails the 39% limit.
Same income, same home, same mortgage — but the stress test changes the answer from pass to fail. To pass, you would need either a higher income, a smaller mortgage, or a larger down payment.
Who must pass the stress test, and who is exempt
The stress test applies to:
- New mortgage applications at federally regulated lenders
- Refinances that increase your mortgage amount
- Switches to a new lender (in most cases)
You generally do NOT need to re-pass the stress test if:
- You renew with your existing lender at the end of your term, without increasing the amount
- You are switching lenders for a straight renewal with no increase, under rules that have been relaxed in recent years (check current rules, as this has changed)
If you are renewing and staying with the same lender, the stress test usually does not block your renewal. This is important, because it means the test mainly affects new purchases and refinances, not existing borrowers renewing their mortgages.
How to improve your chances of passing
There are several legitimate ways to improve your stress test result:
Increase your down payment. A larger down payment means a smaller mortgage, which means a lower stress-tested payment. Saving an extra $25,000 for a down payment can increase your purchasing power by more than $25,000, because it reduces both the mortgage amount and the payment that gets stress-tested.
Pay down other debts. Since TDS includes all debts, paying off a car loan or credit card balance frees up room in your TDS ratio. A $400 monthly car payment, eliminated, can increase your mortgage capacity by roughly $75,000 to $90,000, depending on rates.
Choose a longer amortization if available. A 30-year amortization (available for uninsured mortgages with 20% or more down) lowers the monthly payment compared to 25 years, which helps both GDS and TDS. The trade-off is more total interest paid over the life of the mortgage.
Increase your qualifying income. Lenders use documented, stable income. If you have a side income, rental income, or a recent raise, make sure it is documented and included. Some lenders will count a portion of rental income or investment income, but rules vary.
Consider a less expensive home or a different market. This is not what most buyers want to hear, but the stress test is a hard limit. If you cannot pass at your target price, a slightly lower price or a different neighbourhood may be the practical answer.
What the stress test does not do
The stress test does not guarantee you can afford the mortgage. It is a minimum safety check, not a personal budget. Your actual affordability depends on your full financial picture: childcare costs, transportation, food, savings goals, and emergency reserves are not part of GDS or TDS.
Conversely, failing the stress test does not mean you cannot afford the home. It means a federally regulated lender cannot approve you under current rules. Some alternative lenders, such as credit unions regulated provincially, may have different rules, but they often charge higher rates.
How to check yourself before you apply
Before you apply for a mortgage, run your own stress test:
- Calculate your monthly mortgage payment at your contract rate plus 2%, using Canadian semi-annual compounding.
- Add property taxes, heating, and 50% of condo fees if applicable.
- Divide by your gross monthly income to get GDS. It should be at or below 39%.
- Add all other monthly debt payments, divide by gross monthly income to get TDS. It should be at or below 44%.
- If either ratio is over the limit, adjust your target price, down payment, or debts before you apply.
Doing this check yourself saves you from surprises during the application process and helps you set a realistic budget before you start house hunting.