Buy vs rent guide
The mortgage stress test and buy vs rent
The mortgage stress test is a qualification rule, not a cost, so it does not appear as a line in a buy vs rent comparison. It matters because it sets how much you can borrow, and the same idea is a useful way to test whether buying still works if rates are higher at renewal.
What the stress test is
Under the federal regulator’s minimum qualifying rate, a borrower must show they can afford the mortgage at the greater of their contract rate plus 2 percentage points or 5.25%. The same standard is used for insured mortgages. Straight switches at renewal for uninsured mortgages are exempt, but confirm the current rule with your lender.
The rule exists to make sure households can still pay if rates rise. It does not change the rate you actually pay. If your contract rate is 4.5%, your payment is calculated at 4.5%, but your lender tests you at 6.5%.
Worked examples of the qualifying payment
The payment at the qualifying rate is higher than the payment you actually make. The examples assume a 25-year amortization and semi-annual compounding, which is how Canadian fixed-rate mortgages compound.
| Loan | Contract rate | Qualifying rate | Payment at contract rate | Payment at qualifying rate | Difference |
|---|---|---|---|---|---|
| $480,000 | 3.5% | 5.5% | $2,396.50 | $2,929.88 | $533.38 |
| $480,000 | 4.5% | 6.5% | $2,656.67 | $3,215.15 | $558.48 |
| $480,000 | 6.0% | 8.0% | $3,071.07 | $3,663.42 | $592.35 |
| $400,000 | 3.0% | 5.25% (floor) | $1,892.98 | $2,383.67 | $490.69 |
What the test does to borrowing power
Because lenders limit payments relative to income, a higher qualifying payment means a smaller loan. As an illustration, a payment of $3,215.15 a month supports a $480,000 loan at 6.5% but would amortize about $580,905 at 4.5%. At the same payment, the test takes about $100,905 off the loan size.
That is a simplification. Lenders also look at income, debts, property tax, heating and, for condominiums, a portion of the fee through ratios such as GDS and TDS, so the real limit depends on the full picture. CMHC’s page on GDS and TDS, listed in the sources below, explains the ratios.
Where the stress test meets buy vs rent
The test does not change what the engine calculates. It changes which purchase prices are available to you, and therefore which comparison is the right one. If you qualify for a $600,000 home, compare that home to rent. If the test caps you at $450,000, compare a $450,000 home, which may be a condo or a smaller house, to rent.
Be careful about comparing a bigger home you cannot qualify for with a modest rental. Compare like with like, using the affordability tool to see the price range that fits your income and the mortgage payment tool to see the payment.
Using the idea as a personal stress test
The regulator’s test is a floor. You can apply your own version to the buy vs rent result by raising the rate and asking whether buying still makes sense. Suppose a $600,000 home with 20% down, a 25-year amortization, rent of $2,300 a month and a ten-year hold, with the other calculator defaults. Only the mortgage rate changes. All figures are illustrative.
| Rate | Monthly mortgage payment | First-month owner cost | Break-even | Buyer minus renter at year 10 |
|---|---|---|---|---|
| 3.5% | $2,396.50 | $3,497 | 3.3 years | $95,323 |
| 4.5% | $2,656.67 | $3,757 | 5.7 years | $41,686 |
| 5.5% | $2,929.88 | $4,030 | 15.3 years | -$13,358 |
| 6.5% | $3,215.15 | $4,315 | none found | -$69,616 |
Renewal risk is a stress test too
Most households face a stress test at renewal, even where the regulator’s test does not apply. In the model, a $600,000 home with the 4.5% rate and a five-year term, held ten years, leaves buying ahead by $41,686 if the renewal rate is also 4.5%. If the renewal rate is 6.5%, the result becomes -$2,113. If it falls to 3.0%, the result improves to $73,823.
That is a reason to test the renewal rate separately in the main calculator and to read mortgage renewal risk. A budget that works only at today’s rate leaves little room for the next term.
Questions people ask
What is the mortgage stress test in Canada?
It is a requirement to qualify at the greater of your contract rate plus 2 percentage points or 5.25%. It applies to uninsured mortgages under the federal regulator’s minimum qualifying rate, and the same standard is used for insured mortgages.
Does the stress test change the rate I pay?
No. You pay your contract rate. The test only decides how much you can borrow.
Do I have to pass the test again when I renew?
Straight switches at renewal for uninsured mortgages are generally exempt, but confirm the current rule with your lender, especially if you are changing lenders and increasing the loan.
Does the stress test affect renters?
Not directly, but it limits how much a renter can borrow when buying, which sets the price range to compare against rent.
Official references
Educational information, not financial, tax, legal or mortgage advice. Rules and rates change; confirm current details with an official source or a qualified professional.