The Canada Mortgage and Housing Corporation caps two numbers at 39% and 44%. Miss either one and your mortgage application is finished, no matter how clean your credit report looks or how many years you have banked at that branch.
Those two numbers are your debt service ratios. Gross Debt Service (GDS) measures what housing costs take out of your gross income. Total Debt Service (TDS) adds every other debt payment you carry. Canadian lenders run both at a stress-tested rate rather than the rate you would actually pay, and either ratio can decline your file on its own.
Here is the part nobody explains at the branch: these ratios are arithmetic, not judgement. Nine hundred dollars a month of car and card payments can quietly remove seventy-five thousand dollars of buying power from a file that is otherwise strong. Below is how the math actually works in 2026, the four leaks that push most borrowers over the line, and what your options look like if a bank has already said no. If you have been declined once, our private mortgage options are underwritten on a different set of rules.
How GDS and TDS actually get calculated
GDS is your housing cost divided by your gross monthly income. Four things sit on the top of that fraction: mortgage principal and interest, property taxes, heating costs, and 50% of your condo fees if the property has them. CMHC restricts that ratio to 39%.
TDS starts with everything in GDS and then adds the rest of your obligations. Car loans. Credit card minimums. Student loans.
It also counts the payment on your line of credit, even when the balance sits at zero. That combined total is capped at 44%. The Financial Consumer Agency of Canada publishes the same definitions if you ever want to check a lender's math yourself.
A worked example
Say you earn $7,500 a month before tax, and the property runs $400 a month in property tax and $150 in heat.
GDS at 39% gives you $2,925 for housing. Take out the tax and heat and $2,375 is left for the mortgage payment itself, which supports roughly $339,000 at a 7% qualifying rate over 25 years.
Now add $900 a month of other debt, say a car loan and two card minimums. TDS at 44% gives you $3,300 for everything combined. Remove that $900 and housing drops to $2,400, which leaves $1,850 for the mortgage.
That is about $264,000 of borrowing power. Same income, same credit report, roughly $75,000 less house.
The five-point gap most borrowers miss
Notice that the $900 of debt only cost $75,000 rather than the full $128,000 the payment would suggest. That is because the TDS cap sits five percentage points above the GDS cap, which hands you a built-in allowance for non-housing debt. On a $7,500 monthly income, that allowance is $375 a month. Everything past it comes straight out of your mortgage, dollar for dollar.
Which means affordability, as a Canadian bank defines it, has very little to do with whether you can comfortably make the payment. It has to do with whether two fractions land under two numbers set by a federal Crown corporation.
Why the stress test pushes your ratios higher
Both ratios are calculated at a rate you will never actually pay. Under OSFI rules, every federally regulated lender must qualify you at the higher of your contract rate plus two percentage points, or 5.25%. In early 2026, OSFI confirmed it is leaving that minimum qualifying rate exactly where it is.
So a 4.5% mortgage gets tested at 6.5%. Your real payment might be $2,300 a month. The payment used inside your GDS calculation is closer to $2,750. That gap is why borrowers who have paid rent higher than their proposed mortgage payment for six straight years still fail the test.
Two exemptions worth knowing about
Since November 2024, borrowers with uninsured mortgages can switch lenders at renewal without being stress tested again, as long as the balance and the amortization stay the same. Insured borrowers already had that exemption. If you are renewing and not borrowing more, you have far more room to shop your rate than you did three years ago.
Everything else still gets the full test. Purchases, refinances, any renewal where the balance goes up, and every bank application for a home equity line of credit. The test was built for a rate shock that has already come and gone, and it still sits between a lot of capable borrowers and a mortgage they can plainly afford.
The four ratio leaks that sink most applications
Most declined files are not close calls on income. They are files where four smaller things stacked up. Run this 4-Point Ratio Leak Check before you apply anywhere.
1. Your line of credit limit, not your balance
Lenders count a monthly payment against your unsecured line of credit whether or not you carry a balance. A $50,000 limit you have never drawn on can still register as a few hundred dollars a month of obligation. Closing an unused line before you apply is usually the cheapest fix available to you.
2. Credit card minimums on cards you clear every month
Same logic applies. Paying your balance in full is excellent for your credit report. It does not remove the minimum payment from your TDS calculation. Three cards carrying modest balances can cost you more borrowing room than a car loan does.
3. Income a bank will not count
If you work for yourself, the bank builds your income from your Canada Revenue Agency Notice of Assessment, usually a two-year average of net income after write-offs. The money that moved through your business is not the money on line 15000. Contractors who write off aggressively for tax reasons routinely find their mortgage income is half of what their deposits suggest. Our guide to what Canadian lenders read in your bank statements covers how that gap gets assessed outside the big banks.
4. Estimated property tax and heating figures
Small numbers, real consequences. A lender plugging $250 a month of property tax into a file where the actual bill is $180 has taken $70 a month of borrowing power away from you for no reason at all. Ask which figures were used. Correct them with the real tax bill and the real utility statement.
Honestly, most people we speak with could have passed if someone had walked them through this list eight weeks before they applied. Ratios are fixable. Almost nobody learns that until after the decline letter.
What to do when your ratios fail at the bank
A failed ratio is a math problem, and math problems have more than one solution.
Fix the fraction
Pay out or close the obligation with the largest monthly payment relative to its balance, which is usually a car loan or a store card rather than your biggest debt. Add a co-applicant to raise the income underneath the fraction. Stretch the amortization to 30 years if the file qualifies.
Any one of those can move an application from declined to approved without your income changing at all. Our application process walks through what gets reviewed and when.
Change the lender
Here is the part that gets left out of most explanations. The minimum qualifying rate binds federally regulated lenders. Private lenders and mortgage investment corporations are provincially regulated, in Ontario by the Financial Services Regulatory Authority of Ontario, and they are not required to run your file at contract rate plus two percentage points. They underwrite the property, the equity position, and whether the exit strategy holds up.
That is a different question from whether a fraction lands under 44%. For a self-employed borrower with strong deposits and modest reported income, it is usually a fairer one.
Where Solid Capital fits
Solid Capital is a Canadian alternative lender working with homeowners and business owners the big banks decline or under-serve. We read the full file, meaning bank statements, revenue history, equity position and business context, instead of stopping at a ratio or a credit score. A Canadian advisor reviews every application personally. Start your application at solidcapital.ca: five minutes, no impact to your credit to apply, and a straight answer on where you stand.
Your debt service ratios are a bank's opinion of you, expressed as two decimals. They are not a verdict on whether you can carry a mortgage, and they are not the only underwriting model operating in Canada. Fix what you can fix. Then find a lender who reads the rest.
Frequently Asked Questions
What is a good debt service ratio in Canada?
Under CMHC rules a GDS ratio at or below 39% and a TDS ratio at or below 44% will pass at most Canadian lenders. Many banks apply stricter internal limits, often around 32% GDS, for borrowers with lower credit scores. Sitting below 35% GDS leaves you room to absorb a higher rate at renewal.
How do you calculate GDS and TDS?
GDS is your mortgage payment at the qualifying rate plus property taxes, heating costs and 50% of condo fees, divided by your gross monthly income. TDS is that same total plus every other monthly debt payment, including car loans, credit card minimums, student loans and line of credit payments, divided by the same income figure.
Does the mortgage stress test still apply in 2026?
Yes. Federally regulated lenders still qualify borrowers at the higher of the contract rate plus two percentage points or 5.25%, and OSFI confirmed in early 2026 that the minimum qualifying rate is unchanged. Uninsured borrowers making a straight switch at renewal are exempt, provided the balance and amortization do not change.
Can you get a mortgage if your TDS is over 44%?
Not from a federally regulated lender on an insured file. Private lenders and mortgage investment corporations are provincially regulated and underwrite on equity, property quality and exit strategy rather than debt service ratios alone, so borrowers above 44% are often still fundable. Terms are shorter and pricing is higher than bank financing.
Do credit cards you pay off in full still count toward your TDS?
Yes. Lenders include the minimum monthly payment on every revolving account, and many also count a payment against your unsecured line of credit limit even when the balance is zero. Lowering limits or closing unused accounts before you apply can pull your TDS down measurably.
How much house does a car payment cost you?
Every $100 of monthly debt payment costs roughly $14,000 of mortgage at a 7% qualifying rate over 25 years. There is a catch worth understanding: because the TDS cap sits five points above the GDS cap, the first few hundred dollars of monthly debt is absorbed by that gap. Past that point, every dollar of payment reduces your mortgage directly.
