Mortgage Stress Test Canada 2026: How to Calculate and Pass B-20

Canada's B-20 mortgage stress test has reshaped what Canadians can afford to borrow since it was introduced in 2018. It's also one of the most misunderstood rules in Canadian real estate. This guide explains exactly how it works, how to calculate your maximum purchase price, and practical strategies to increase your buying power within the rules.

What Is the B-20 Stress Test?

The B-20 guideline (issued by OSFI — the Office of the Superintendent of Financial Institutions) requires Canadian mortgage lenders to qualify borrowers at a higher rate than their actual mortgage rate. The idea is to ensure borrowers can still afford their mortgage if rates rise after purchase.

The qualifying rate is the higher of:

Your contract mortgage rate + 2%, or
5.25% (the minimum qualifying rate)

So if your bank offers you a 5-year fixed rate of 5.0%, you qualify at 7.0% (5.0% + 2%). If rates drop and your contract rate is 3.0%, you still qualify at 5.25% (the floor).

Contract Rate	+2% Rate	Floor Rate	Qualifying Rate
3.0%	5.0%	5.25%	5.25% (floor applies)
4.0%	6.0%	5.25%	6.0% (+2% applies)
5.0%	7.0%	5.25%	7.0% (+2% applies)
5.5%	7.5%	5.25%	7.5% (+2% applies)
6.0%	8.0%	5.25%	8.0% (+2% applies)

GDS and TDS: The Two Debt Ratio Tests

The stress test works through two debt ratio calculations. You must pass both.

Gross Debt Service (GDS) Ratio

GDS measures housing costs as a percentage of gross income. The limit is 39%.

GDS = (Mortgage Payment + Property Tax + Heating + 50% Condo Fees) ÷ Gross Monthly Income

Note: Mortgage payment is calculated at the qualifying rate, not your contract rate.

Total Debt Service (TDS) Ratio

TDS includes all debt payments, not just housing. The limit is 44%.

TDS = (GDS components + Car payments + Credit card minimums + Student loans + Other debts) ÷ Gross Monthly Income

Worked Example: How Much Can You Afford?

Scenario: $120,000 household income, 10% down, 5.5% rate

Step 1: Determine qualifying rate

5.5% contract + 2% = 7.5% qualifying rate

Step 2: Calculate maximum GDS

Max housing costs = $120,000 × 39% ÷ 12 = $3,900/month

Step 3: Subtract property costs

Property tax: ~$500/month | Heating: ~$150/month

Remaining for mortgage at qualifying rate: $3,250/month

Step 4: Back-calculate maximum mortgage

At 7.5% qualifying rate, 25-year amortization: ~$450,000 mortgage

Maximum purchase price: ~$500,000

($450K mortgage + $50K down payment, before CMHC on the 10% down)

⚠️ The Stress Test Gap

At a 5.5% contract rate, your actual monthly payment on a $450K mortgage would be ~$2,750 — but you qualified at $3,250/month (the 7.5% stress test rate). This ~$500/month buffer is intentional: if rates rise to 7.5%, you've already proven you can afford it.

How the Stress Test Affects Different Income Levels

Household Income	Max at 5% Rate	Max at 5.5% Rate	Max at 6% Rate
$80,000	~$370,000	~$345,000	~$320,000
$100,000	~$465,000	~$430,000	~$400,000
$120,000	~$555,000	~$515,000	~$480,000
$150,000	~$695,000	~$645,000	~$600,000
$200,000	~$925,000	~$860,000	~$800,000

Assumes 10% down, $400/mo property tax, $150/mo heating, no other debts, 25-yr amortization.

Strategies to Pass the Stress Test (Or Increase Your Limit)

1. Increase Your Down Payment

A larger down payment reduces your required mortgage, which directly reduces the GDS-calculated payment at the stress test rate. Going from 5% to 10% down on a $600K property reduces your mortgage by $30K and your stress-test payment by ~$225/month.

2. Pay Down Existing Debts

TDS is the binding constraint for many buyers with car loans or credit card debt. Paying off a $400/month car loan before applying can increase your maximum purchase price by $50,000–$80,000.

3. Add a Co-Applicant

Adding a spouse, partner, or family member as a co-applicant includes their income in the GDS/TDS calculation. A co-applicant earning $60,000/year can increase your buying power by $200,000–$300,000, depending on their existing debt load.

4. Extend Your Amortization

If you have 20%+ down, you can qualify for a 30-year amortization (uninsured mortgage). This reduces your stress-test qualifying payment, allowing you to qualify for a larger mortgage — though you'll pay significantly more total interest over 30 years vs 25.

5. Use a Monoline or Credit Union Lender

Provincial credit unions are provincially regulated, not federally. Some credit unions do not apply the OSFI B-20 stress test or use a modified version. This can allow qualification at lower stress test rates. Check with a mortgage broker who works with credit unions in your province.

Frequently Asked Questions

Does the stress test apply to renewals?

Since November 2024, the stress test no longer applies to insured mortgage renewals (5%–20% down) if you switch lenders. This was a significant change that allows borrowers with insured mortgages to shop for better rates at renewal without re-qualifying under the stress test at the new lender.

Does the stress test apply to refinancing?

Yes. If you refinance (as opposed to renewing at the same terms with the same lender), you must re-qualify under the stress test. This is why some homeowners choose to stay with their current lender at renewal even if rates are slightly higher — avoiding the stress test hurdle.

Is the stress test the same for all lenders in Canada?

Federally regulated lenders (banks, federal credit unions) must follow OSFI's B-20 guidelines. Provincially regulated credit unions and some private lenders may use different qualifying criteria. Always confirm with your lender or mortgage broker.

Calculate your exact maximum purchase price under the B-20 stress test using the Affordability Calculator — it applies the qualifying rate automatically, includes GDS/TDS ratios, CMHC insurance, and land transfer tax for your province. Free, no login required.