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Debt service ratio calculator (GDS & TDS)

Work out your gross and total debt service ratios (GDS and TDS) — the measures Canadian lenders use to qualify you, with GDS up to 39% and TDS up to 44%.

By Mitch Duncan Last reviewed Methodology

Your income & debts

Mortgage or rent, plus property tax, building/home insurance, and any HOA / strata / service charge.

Car loans, student loans, credit-card minimums, personal loans. Exclude utilities, groceries, and other living costs.

Sum of all balances incl. mortgage. Used for the income-multiple measure lenders use as a sense-check.

Canadian lenders qualify you with GDS ≤ 39% and TDS ≤ 44%, tested at the higher of your rate + 2% or the 5.25% stress-test minimum.

GDS — gross debt service
25.0%
TDS — total debt service
35.0%
Within lender guidelines

Your total-debt ratio of 35% is at or below the 44% lenders look for — a healthy position that should qualify you with most lenders.

Lender guidelines — CA
GDS — gross debt service — recommended max
39%
TDS — total debt service — recommended max
44%
Income multiple — typical cap
4.5×

DTI uses gross (pre-tax) income, the same basis lenders apply. It's a guide — actual approval also depends on credit history, deposit, employment, and the lender's own stress test.

Want the full picture? How Much House Can I Afford? The 28/36 Rule Explained →

GDS and TDS — Canada's debt service ratios

Canadian mortgage lenders qualify you using two debt service ratios:

GDS = housing ÷ gross income · TDS = all debt ÷ gross income

The mortgage stress test

Both ratios are tested at the higher of your contract rate + 2% or the 5.25% qualifying rate. So you must show you could afford payments at a rate well above the one you're offered — a deliberately conservative buffer that limits how much you can borrow.

Worked example

Gross income $7,000/month, housing $2,400, other debts $500. GDS = 34%, TDS = 41% — both inside the 39/44 limits, so you'd typically qualify.

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Frequently asked questions

What is a debt-to-income ratio?
Your debt-to-income (DTI) ratio is the share of your gross monthly income that goes toward debt payments. Divide your total monthly debt by your gross monthly income and multiply by 100. Lenders use it to judge whether you can comfortably afford to take on more borrowing — the lower your DTI, the more room you have.
What's the difference between front-end and back-end DTI?
The front-end ratio counts only housing costs — mortgage or rent, property tax, insurance, and any service charge — against your gross income. The back-end ratio counts all your debt: housing plus car loans, student loans, credit-card minimums, and personal loans. The back-end ratio is usually the figure lenders use to make a decision.
What's a good debt-to-income ratio?
Lower is better. As a general guide, a back-end ratio at or below the mid-30s percent is considered healthy, the low-40s is borderline, and above the mid-40s makes borrowing harder. The exact limits depend on your country and lender — the calculator above compares your ratio to the thresholds used in your region.
Does DTI use gross or net income?
Gross income — your pay before tax and deductions. Lenders use gross income because it's the consistent figure shown on payslips and tax returns. Bear in mind your real budget is tighter than your DTI suggests, since tax and other deductions come out before you see the money, so staying well under the limit leaves breathing room.
What debts are included in the calculation?
Include recurring debt: your mortgage or rent, car loans, student loans, credit-card minimum payments, personal loans, and any court-ordered payments like child support. Exclude everyday living costs such as utilities, groceries, insurance (other than on your home), subscriptions, and discretionary spending — those aren't debts.
How can I lower my debt-to-income ratio?
Pay down or clear debts with high monthly payments — removing a car loan or credit-card balance takes its payment out of the ratio entirely. Avoid taking on new debt in the months before applying for a mortgage, and increasing your income raises the bottom of the ratio. Refinancing to a longer term lowers the monthly payment too, though it can cost more interest overall.

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