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GDS and TDS Calculator: What Are Your Debt Service Ratios?
Quick answer: Your gross debt service ratio (GDS) is the share of your gross income that goes to housing: the mortgage payment at the stress test rate, property tax, heating and half of any strata fee. Your total debt service ratio (TDS) adds every other debt payment. For an insured mortgage, lenders accept up to 39% GDS and 44% TDS.
What are your GDS and TDS ratios?
Enter the mortgage you have in mind and your monthly costs. Ratios use the stress test rate, as lenders do.
Gross debt service (GDS)
38.8%
Within the 39% limit
Total debt service (TDS)
42.8%
Within the 44% limit
- Qualifying payment of $3,425 a month at 6.75% (your actual payment at 4.75% is about $2,837)
- Housing costs counted: $3,875 a month
- Your other debt payments could rise by about $125 a month before reaching the 44% limit.
Estimate only. Insured mortgages allow up to 39% GDS and 44% TDS of gross income at the higher of your rate plus 2% or 5.25%. Some lenders use lower limits, and lenders count debts such as credit cards and lines of credit in their own ways. The default rate is our current 5 year fixed rate. Book an appointment for a review of your numbers.
How are GDS and TDS calculated?
Lenders add up your monthly costs and divide by your gross monthly income:
- GDS = (mortgage payment + property tax + heating + half the strata fee) ÷ gross monthly income
- TDS = (all GDS costs + other monthly debt payments) ÷ gross monthly income
The mortgage payment is worked out at the qualifying rate, which is the higher of your contract rate plus 2% or 5.25%. With our current 5 year fixed rate of 4.75%, that means qualifying at 6.75%.
What are the limits?
| Mortgage type | GDS limit | TDS limit |
|---|---|---|
| Insured (less than 20% down) | 39% | 44% |
| Uninsured at many banks | 35% to 39% | 42% to 44% |
| B lenders | Often up to 50% | Often up to 50% |
Limits vary by lender and by file; credit score, down payment and the property all play a part.
What if your ratios are too high?
High ratios do not always mean no. A different lender, a co borrower, a longer amortization or paying off one debt can bring you inside the limits. Our debt repayment calculator shows how fast you can clear a debt, and the BC affordability calculator turns your ratios into a purchase price. If a bank says no, a B lender may accept higher ratios at a higher rate.
Frequently asked questions
What GDS and TDS ratios do I need for a mortgage in Canada?
For an insured mortgage (less than 20% down), CMHC allows up to 39% GDS and 44% TDS of gross income. Many lenders use the same limits for uninsured mortgages, and some use lower ones such as 35% and 42%.
Are GDS and TDS worked out at my actual mortgage rate?
No. Lenders use the qualifying rate under the stress test: the higher of your contract rate plus 2% or 5.25%. That is why your ratios look higher than your real budget.
Which debts count in the TDS ratio?
Car loans and leases, student loans, personal loans, support payments and the payments on credit cards and lines of credit. Lenders often count a card at 3% of its balance and a line of credit at an interest only or 3% payment, even if you pay less.
How can I lower my TDS ratio before applying?
Pay off or pay down small debts with high payments, avoid new car loans or credit before you apply, add a co borrower's income, or choose a smaller mortgage or a longer amortization where you qualify for one.
Want a lender's view of your numbers? Book an appointment with Asim Ali, ranked #4 in the CMP Top 75 Mortgage Brokers in Canada for 2026, or call 604‑591‑3590.