How the mortgage stress test works in Canada

What the mortgage stress test is

The mortgage stress test is one rule with a long name: the minimum qualifying rate, set out in OSFI Guideline B-20.

Lenders must qualify you at the greater of your contract rate plus 2 percentage points, or 5.25%.

You're approved at a rate about 2 points higher than the one you'll pay, and the mortgage you qualify for is the one you could carry at that higher rate. At today's rates, "contract rate plus 2" is almost always the higher figure. A 4.09% mortgage is qualified at 6.09%, not 5.25%.

The rule applies to federally regulated lenders: the banks, and in practice the monolines that fund through them. Default-insured mortgages follow an equivalent rule set by the insurers. OSFI reaffirmed the buffer in January 2026.

The test is there to make sure a household taking a mortgage today could still carry it at renewal if rates were much higher. Anyone who signed in 2021 and renewed in 2026 saw why.

How the stress test affects what you can borrow

The test cuts roughly 18 to 20% of your purchasing power compared with qualifying at the contract rate. The exact figure depends on your ratios, your amortization and your other debts, but most files land in that range.

Here's how it works, step by step:

1. Your qualifying rate is contract plus 2 points, or 5.25%, whichever is higher.
2. Your qualifying payment is calculated at that rate, over your actual amortization.
3. That qualifying payment, plus property taxes, heat and half of any condo fee, goes into your gross debt service ratio.
4. Add every other monthly debt payment and you get your total debt service ratio.
5. Both ratios have to come in under their limits.

Only the rate changes. Your amortization, property costs and income stay the same, and the payment follows the rate.

For example, at 4.09% over 25 years, $500,000 costs about $2,660 a month. At the qualifying rate of 6.09%, the same $500,000 costs about $3,230. Your ratios are tested against the second number, while you'd pay the first.

When the stress test doesn't apply

There are 3 exceptions. The second one is recent, and many borrowers haven't heard of it.

A straight renewal with your current lender isn't stress-tested. It never has been. If you stay with your lender and sign, no qualifying test applies.

Since November 2024, an uninsured straight switch to a new lender isn't stress-tested either. Same borrower, same property, same balance, same remaining amortization, different lender: you qualify at the contract rate. Before this change, borrowers could get stuck with their current lender, and lenders priced renewals knowing it. There are 2 conditions. The balance can't increase and the amortization can't be extended. Change either and it becomes a refinance.

Provincially regulated credit unions are outside OSFI's jurisdiction. More on that below.

Everything else is tested: purchases, refinances, balance increases, and any transaction that isn't a like-for-like move.

GDS and TDS ratios

The stress test gets the headlines, but it's one of 3 limits, and often it isn't the one that decides your file.

Gross debt service (GDS) is your housing cost as a share of your gross income: the qualifying mortgage payment, property taxes, heating, and 50% of any condo fee. The insured guideline is 39%.

Total debt service (TDS) adds everything else you pay monthly: car payments, lines of credit, student loans and support payments. It also counts the payment on the full limit of any credit card or HELOC, whether you carry a balance or not, which catches a lot of people. The insured guideline is 44%.

An unused $30,000 line of credit still takes up room in your ratios. Closing it can add five figures to what you can borrow, and it's the cheapest fix on the list.

Lenders can go above the guidelines on a strong file, meaning a solid down payment, high credit, long job tenure and provable income. That flexibility shrinks quickly as the ratios rise.

If you're buying in Edmonton, property tax makes a noticeable difference here. At roughly 1.0% of assessed value all-in, a $470,000 Edmonton home carries about $390 a month of property tax in the GDS ratio before the mortgage is counted.

Credit unions and the stress test

Alberta credit unions are regulated by the province, not OSFI, so they're not bound by Guideline B-20. They set their own qualifying rules.

People misread this in both directions. Credit unions do underwrite, and some are stricter than the banks on property type, income documentation or both. But a file that fails one bank's minimum qualifying rate can sometimes be placed at a credit union that uses a different standard.

That's one reason a brokerage can sometimes place a file that a branch can't. A branch can only apply its own lender's rules, and Alberta has more than one set.

We don't treat it as a loophole. A file that only works because it found a lender with a lower bar has no margin, and at renewal in 5 years you'd face the same problem with fewer options.

How to pass the stress test

These are in rough order of effect for the effort involved.

Pay off small monthly debts. A $550 car payment removes roughly $90,000 to $110,000 of purchasing power on a typical file. Paying off a vehicle loan, or not taking one on, is usually the biggest lever you control.

Close or reduce unused credit. TDS counts the payment on your full available limit, so an unused line of credit only costs you in this calculation.

Add a co-borrower with income, if that's an option for you. A parent on title changes the ratios directly. It changes their tax position too, so talk to an accountant as well as a broker.

Extend the amortization. A 30-year amortization instead of 25 years lowers the qualifying payment. On an insured mortgage, this is available to first-time buyers and buyers of new builds, for an extra 0.20% on the premium. It costs 5 more years of interest.

Increase the down payment. This takes time, and there's a catch many people don't expect: crossing 20% moves you out of the insured tier and usually into a higher rate, which slightly raises your qualifying rate. It's still usually the right move above that threshold, but the gain is smaller than it looks.

Document income you're not getting credit for. That includes overtime with a 2-year history, a bonus that's in your contract (not discretionary), or a legal basement suite with a lease and a permit. Plenty of files fail because the income was there but not documented.

Run the numbers before you change anything. The stress test calculator shows your qualifying rate and both ratios, and tells you which ratio is limiting you. That tells you which fix above is worth your time.