GDS / TDS Calculator
Your two debt service ratios, worked out the way a Canadian lender does: at the stress-test rate, with cards counted at 3% of the balance and half the condo fees. If you are over 39% or 44%, it shows what gets you under.
Half of the condo fees count. Heat should be the home's real cost where you have it.
- Room left: $268 a month under GDS and $768 under TDS.
- The largest mortgage these numbers carry: $542,782 (GDS is the tighter of the two).
- Mortgage payment at 6.50%
- $3,132
- Property tax
- $400
- Heat
- $100
- Housing costs (GDS)
- $3,632
- Housing plus debts (TDS)
- $3,632
- Monthly income used
- $10,000
What you would actually pay at 4.50%: $2,521 a month. The ratios use the higher qualifying payment, as every federally regulated lender must.
- Works out the stress-tested payment itself, at the greater of your rate plus 2% or 5.25%, where most ratio calculators make you type a payment in
- Counts debts the way CMHC tells lenders to: cards and unsecured lines at 3% of the balance, a secured line paid off over 25 years at its own rate
- Counts suite rent the CMHC way: up to half of it, or up to all of it on a two-unit home you live in
- When a ratio fails, shows what fixes it: the mortgage that fits, the debt to clear, or the income that would carry it
Over the line, or close to it?
Debts can be counted differently, income documented better, and the mortgage placed with a lender whose limits fit the file. We'll run your exact numbers. Free, no obligation, same-day reply.
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Common questions
What are GDS and TDS?+
They are the two debt service ratios every Canadian lender checks. GDS (gross debt service) is your mortgage payment, property tax and heat, plus half of any condo fees, divided by your gross income. TDS (total debt service) is the same plus all your other debt payments. CMHC caps insured mortgages at 39% GDS and 44% TDS.
What rate do lenders use to work out my ratios?+
Not your actual rate. The mortgage payment in both ratios is worked out at the qualifying rate: the greater of your contract rate plus 2%, or 5.25%. CMHC applies it to insured mortgages, and OSFI requires federally regulated lenders to apply the same test to uninsured ones.
How are credit cards and lines of credit counted?+
Credit cards and unsecured lines of credit count at no less than 3% of the balance each month, whatever your minimum payment is. A secured line of credit counts as at least the payment that would pay its balance off over 25 years at its own rate. Car loans and other loans count at their actual payment.
Can rent from a suite help me qualify?+
Yes. When the suite is in the home you are buying, CMHC allows up to 50% of the gross rent to be counted as income, and up to 100% of the second suite's rent on a two-unit home you live in. Lenders decide where they sit within those limits.
What if my ratios are over 39% or 44%?+
Those are CMHC's limits for insured mortgages. Other lenders set their own, and a file over the line can often be put together differently: a smaller mortgage, a debt paid off before closing, a co-applicant's income, or a 30-year amortization where the program allows it. The calculator shows the size of each fix for your numbers.
Should the mortgage amount include the CMHC premium?+
Yes. CMHC bases the qualifying payment on the loan amount including the mortgage insurance premium, so enter the mortgage with the premium added when you are putting less than 20% down.
Case Studies — files like this
Anonymized case studies from our files. Names and identifying details removed.
- Case study · Residential / AlternativeBuying Out a Half Owner in Maple Ridge: An Alternative-Lender Refinance at 70% on Homestay and Suite IncomeBuying out a half owner on one fixed salary and non-taxable homestay income with no pay stubs: an alternative lender refinanced the Maple Ridge house at 70% in 2021, $1,050,000, grossing the homestay and child benefit up 25%.Read the file →
- Case study · Residential / PrimeRideshare Income and 10% Down: A Major Bank's Insured Mortgage Bought a First Condo in Delta at 90%A self-employed rideshare driver and a draftsperson bought their first home, a Delta condo, at 90% in 2024 with a major Canadian bank's insured mortgage, $432,000 plus the premium at about 4.8%, the driving income averaged over two years and grossed up by 15%.Read the file →
- Case study · Residential / PrimeRatios Near 46% and a Job Under a Year Old: A Major Bank Financed a First Home With a Suite in Delta at 80%A first-time couple with ratios near 46% and one job under a year old bought a five-bedroom Delta home with a suite at 80% in 2025, $1,118,400 at 4.55% from a major Canadian bank, helped by a $160,000 gift from a parent.Read the file →
Where the rules come from: the limits, the 3% card rule, the 25-year secured line rule, the suite rent shares and the qualifying rate are CMHC's, read on October 18, 2026; the same qualifying rate for uninsured mortgages is OSFI's. CMHC, Calculating GDS / TDS · OSFI, Minimum qualifying rate for uninsured mortgages
Want the other direction, how big a mortgage your income carries? Use the affordability and stress test calculator → Self-employed, or carrying debts you want to fold in? See self-employed mortgages · stated income · debt consolidation.
Every calculator here is built on published Canadian government rules and lender methodology. This one was built and checked for accuracy on October 18, 2026 — the arithmetic verified against those rules and the page re-read on screen. Rates and thresholds change — we confirm the current numbers for your file before you rely on them.