Nearly every buyer I work with has heard the term "stress test" without quite knowing what it does to their actual number. Here's the plain version, including the part that matters specifically if you're buying a condo.
The basic rule
Federally regulated lenders, meaning the banks, have to qualify you at the higher of two numbers: your actual contract rate plus 2 percentage points, or a floor rate set by the regulator, currently 5.25%. In today's rate environment, with five-year fixed rates commonly landing in the low 4% range, contract-plus-2% almost always wins out. A 4.4% contract rate means you're actually qualified at roughly 6.4%, even though that's not the rate you'll pay.
Why it exists
It's a safety buffer, introduced by Canada's banking regulator to make sure borrowers can still handle their payments if rates climb before their term is up. It reduces how much everyone can borrow, on the order of 15 to 20% less than they'd qualify for at the actual contract rate. That's a real, meaningful haircut on your purchasing power, worth knowing before you start touring units above your comfortable range.
The part that matters specifically for condo buyers
Lenders calculate your debt service ratio using your mortgage payment, property tax, heating costs, and half of your condo maintenance fees. That last piece catches people off guard. A building with high maintenance fees doesn't just cost more monthly, it can measurably reduce how much mortgage you qualify for in the first place, since half of that fee gets added into the affordability math before a bank tells you your maximum.
A practical example
Two identical-priced units, one with $500 monthly fees, one with $800. On the higher-fee unit, an extra $150 a month gets counted against your affordability ratios. It won't sink a strong application, but on a borderline one, it can be the difference between qualifying for the unit you want and needing to look at something less expensive. This is one more reason building-specific fee comparisons matter more than people expect going in.
The one exemption worth knowing
If you're simply renewing your existing mortgage or switching lenders at renewal without increasing your loan amount or extending your amortization, you're generally exempt from re-qualifying under the stress test. That exemption doesn't help you on a new purchase, but it's useful to know if you already own and are wondering what to expect down the line.
Before you set a budget in your head, it's worth getting a real pre-approval from a lender or mortgage broker who can run your actual numbers through the stress test, not just a rough online calculator. I can point you toward people I trust if you don't already have one.