GDS compares housing costs to your gross income
TDS includes housing + other debt payments
Lenders use these to measure risk before approval
Lower ratios generally improve mortgage approval chances
Enter your income and debt details in the calculator above
Understanding how much mortgage you can afford starts with your debt service ratios — metrics lenders use to assess your ability to repay mortgage and other debts.
Use our Debt Service Calculator to estimate:
Gross Debt Service (GDS)
Total Debt Service (TDS)
This page explains what these ratios mean, how they’re calculated in Canada, and why they matter when applying for a mortgage. We also reference authoritative guidance so you can plan confidently.
At Citadel Mortgages, we help you understand your financial picture — and how to improve it.
Whether you’re a first-time homebuyer, refinancing, or renewing your mortgage, understanding current trends and available options helps you make informed financial decisions.
This guide focuses on helping you navigate the Canadian mortgage market, offering insights into current rates, strategies for securing the best deal, and regional trends.
Mortgage brokers play a pivotal role in helping Canadians find tailored financing options, providing expert advice, and navigating the often complex mortgage market.
For more detailed information on mortgage types, costs, and rights, consult the Government of Canada – Financial Consumer Agency of Canada (FCAC).
Debt service ratios are financial measures lenders use to evaluate whether a borrower’s income sufficiently covers housing and other debt obligations.
GDS estimates how much of your before-tax income goes toward housing costs:
Formula:
Where:
P = Principal
I = Interest
T = Property Taxes
I = Insurance
TDS looks at housing plus other recurring debt payments (e.g., car loans, credit cards):
Formula:
Lenders in Canada use both ratios — GDS and TDS — to estimate affordability and repayment capacity.
Today’s Mortgage Rates updated as of April 15, 2026 10:33 am
Lenders use debt service ratios to manage risk and comply with mortgage underwriting standards. A lower ratio generally signals that you’re in a stronger position to carry mortgage payments plus other debt.
Typical benchmark ratios (varies by lender and program):
GDS ≤ 39%
TDS ≤ 44%
These are general guidelines, not absolutes, and exceptions may apply depending on credit strength, down payment, and lending program.
Enter your total gross monthly income.
Add your monthly housing costs (mortgage, taxes, heat, etc.).
Include all monthly debts (loans, credit cards, car payments).
The calculator instantly shows your GDS and TDS ratios — and whether you meet lender standards.
💡 Tip: Most lenders prefer GDS ≤ 39% and TDS ≤ 44%. Staying within these limits gives you the best chance of mortgage approval.
The Citadel Mortgages Debt Service Calculator follows Canadian lending standards used by major banks, credit unions, and mortgage brokers nationwide, including:
🏙️ Toronto, ON | 🌲 Vancouver, BC | 🏔️ Calgary, AB | 🌅 Halifax, NS
Whether you’re buying, refinancing, or renewing, this calculator helps you plan ahead and avoid surprises.
In Canada, lenders and mortgage insurers use debt servicing metrics as part of their underwriting criteria.
For example, the Financial Consumer Agency of Canada explains that mortgage decisions consider:
Income
Down payment
Credit history
Debt service ratios
This helps ensure consumers understand total borrowing costs.
If your initial ratios are high (above common benchmarks), you can:
Increase your down payment
Reduce non-mortgage debt
Increase documented gross income
Choose a longer amortization (where appropriate)
These strategies may improve approval chances, but every file is unique.
✅ Accurate GDS/TDS results aligned with lender policies
💡 Find weak spots before applying for a mortgage
💳 See how debt impacts qualification
📈 Plan to lower ratios and boost approval odds
🤝 Connect with advisors who can help you restructure for approval
Monthly Income: $8,500
Mortgage Payment: $2,200
Property Taxes & Heat: $450
Other Debts (loans, cards, etc.): $750
GDS Ratio: 31.2% ✅ (within limit)
TDS Ratio: 40.5% ✅ (within limit)
💡 This borrower qualifies for most Canadian lenders. A small debt reduction could increase approval options further.
Lenders may also consider:
Employment stability
Credit score and history
Asset reserves (savings, investments)
Type of mortgage product
Down payment source and documentation
Ratios are one part of a comprehensive risk assessment.
Most Canadian lenders require GDS ≤ 39% and TDS ≤ 44% to qualify for a mortgage.
Yes — alternative or B-lenders often allow higher ratios with compensating factors like higher income, large down payment, or strong credit.
Yes, it includes heat and 50% of condo fees by default.
Pay down credit cards, consolidate loans, or increase your down payment — our advisors can help you plan this effectively..
Yes. It’s based on national underwriting standards used across Canada.
Simplify your financial planning with our full calculator suite:
At Citadel Mortgages, we help Canadians turn their homeownership dreams into reality.
Here’s what makes us Canada’s trusted choice:
🌟 Access to Top Lenders Nationwide
💼 Customized Mortgage Solutions for Every Buyer
📈 Award-Winning Rates & Expert Guidance
🤝 Dedicated Support from Pre-Approval to Closing
Use our Debt Service Calculator to find out if your GDS and TDS meet lender requirements — and let Citadel Mortgages show you how to improve them for a faster approval.
👉 Check My Mortgage Rate Options
👉 Apply Now for Your Best Rates