Debt service calculator
Instantly calculate Canadian GDS/TDS ratios with the current mortgage stress test.
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Interactive calculator
Debt service calculator
See your Canadian mortgage stress test ratios (GDS/TDS), highlight risk bands, and understand how income + expenses impact approvals.
Calculation notes
Methodology for the debt service calculator
Calculate your Gross Debt Service (GDS) and Total Debt Service (TDS) ratios — the two key metrics lenders use to assess your mortgage application.
See exactly how each monthly obligation — mortgage, property taxes, heating, condo fees, car loans, credit cards — affects your ratios.
Compare your ratios against standard lender thresholds (39% GDS, 44% TDS) to identify which expenses are pushing you over the line.
Build a debt-reduction plan: which loan to pay off first for the biggest ratio improvement and maximum mortgage boost.
Inputs to check
- Gross monthly income
- Housing costs (mortgage, taxes, heating, condo fees)
- Other monthly debt payments
Assumptions
- Uses standard GDS/TDS ratio thresholds that individual lenders may adjust.
- Assumes consistent income and debt levels; variable income requires additional documentation.
- Credit card payments are estimated at 3% of outstanding balance per standard lender practice.
- Does not replace full underwriting — final ratios verified by the lender with documented income and debts.
How this calculator works
Calculate your Gross Debt Service (GDS) and Total Debt Service (TDS) ratios — the two key metrics lenders use to assess your mortgage application.
See exactly how each monthly obligation — mortgage, property taxes, heating, condo fees, car loans, credit cards — affects your ratios.
Compare your ratios against standard lender thresholds (39% GDS, 44% TDS) to identify which expenses are pushing you over the line.
Build a debt-reduction plan: which loan to pay off first for the biggest ratio improvement and maximum mortgage boost.
Inputs you will need
- Gross monthly income
- Housing costs (mortgage, taxes, heating, condo fees)
- Other monthly debt payments
Assumptions and limitations
- Uses standard GDS/TDS ratio thresholds that individual lenders may adjust.
- Assumes consistent income and debt levels; variable income requires additional documentation.
- Credit card payments are estimated at 3% of outstanding balance per standard lender practice.
- Does not replace full underwriting — final ratios verified by the lender with documented income and debts.
Example scenarios
Targeting 39/44 ratios
On $10K gross monthly income with $2,800 mortgage, $400 taxes, $150 heating, and $500 car loan — GDS is 33.5% and TDS is 38.5%. Both pass with room to spare.
Car loan elimination impact
Removing a $600/month car payment improves TDS by 6 percentage points on $8K monthly income — often the difference between approval and decline.
Adding a co-borrower
Adding a co-borrower with $60K income and no debt improves all ratios proportionally and can increase max mortgage by $120K-$150K.
Condo fee sensitivity
A $500/month condo fee adds 5 percentage points to GDS on $10K income — enough to push a borderline file over the limit. Run the condo scenario before committing.
Related tools
Turn this purchase result into a plan
Pair the calculator output with the right buyer guide, then pressure-test lender fit, down payment, and closing-day cash before you make an offer.
Guides
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Execution
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Frequently asked questions
What is GDS and why does it matter?
GDS — Gross Debt Service — is your monthly housing costs (mortgage, taxes, heating, 50% of condo fees) divided by gross monthly income. Lenders cap GDS at 39%. If your GDS is too high, you need a larger down payment, lower-rate mortgage, cheaper property, or higher income.
What is TDS and how is it different?
TDS — Total Debt Service — is GDS plus all other monthly debt payments (car loans, credit cards, lines of credit, student loans) divided by gross income. Lenders cap TDS at 44%. TDS is more restrictive for most borrowers because it captures all debts.
Do all lenders use the same GDS/TDS limits?
No. 39% GDS and 44% TDS are common benchmarks, but some lenders allow higher ratios for strong borrowers — up to 44% GDS and 48-50% TDS with compensating factors like high credit scores or large liquid assets. Insured mortgages tend to have firmer limits.
How are credit card payments calculated in TDS?
Lenders typically use 3% of the outstanding balance as the monthly payment, regardless of what you actually pay. A $10K balance adds $300 to TDS — even if your minimum payment is lower. Paying off credit cards before applying is one of the highest-ROI moves.
Do bonuses and variable income count toward ratios?
Lenders require a two-year history and average variable income. A $20K annual bonus over two years adds ~$1,667/month to qualifying income. Self-employed income uses the two-year average of line 15000 from your Notice of Assessment.