What DTI ratio do I need for a mortgage?

In the US, lenders commonly target a DTI around 43% or below — the long-standing Qualified Mortgage benchmark, which the CFPB shifted in 2021 from a hard 43% cap to an APR-based price test, so some lenders allow up to 50% with strong compensating factors. For the best rates, aim for under 36%. FHA loans allow up to 57% DTI in some cases. In Canada, the Total Debt Service (TDS) ratio must be ≤44% and Gross Debt Service (GDS) ≤39%.

How does the UK assess debt affordability for mortgages?

UK lenders don't use a fixed DTI limit but conduct affordability assessments. They stress-test your ability to repay if interest rates rise by 3%. Most lenders will lend up to 4–4.5× your annual income. The FCA's Mortgage Market Review requires responsible lending assessments based on income and expenditure.

What is Canada's GDS and TDS ratio?

GDS (Gross Debt Service) ratio includes only housing costs (mortgage P&I, property tax, heating) divided by gross income — must be ≤39%. TDS (Total Debt Service) includes all debt payments divided by gross income — must be ≤44%. Both apply to federally regulated lenders in Canada for insured mortgages.

🇺🇸 US ~43% DTI benchmark🇬🇧 UK affordability test🇨🇦 TDS ≤44% GDS ≤39%🇦🇺 Australia income-based

Debt-to-Income Ratio Calculator

Your DTI ratio is the key metric lenders use to approve mortgages and loans. The US commonly targets 43%, Canada uses TDS/GDS, and the UK uses an affordability stress test — understand which applies to you.

Quick Answer

DTI = total monthly debt payments ÷ gross monthly income, expressed as a percentage. US lenders commonly target 43% DTI — the Qualified-Mortgage benchmark, which since 2021 is an APR-based price test rather than a hard cap; Canada uses TDS ≤44% and GDS ≤39%; the UK relies on an affordability stress test (typically lending 4–4.5× income) rather than a single fixed ratio.

📊 US standard: Max DTI for conventional mortgage is 43–50%. UK: No fixed limit, but lenders stress-test at higher rates. Canada: TDS ≤ 44%, GDS ≤ 39%.

Gross Monthly Income ($)

Monthly Debt Payments

DTI / Affordability Rules by Country

Country	Max DTI / Ratio	Method
🇺🇸 United States	43% (conv.) / 57% (FHA)	All monthly debt ÷ gross monthly income
🇬🇧 United Kingdom	No fixed limit	Stress test at +3% rate; typically 4–4.5× income
🇨🇦 Canada	TDS ≤44%, GDS ≤39%	GDS = housing costs ÷ income; TDS = all debt ÷ income
🇦🇺 Australia	No fixed limit	Net income surplus; HEM benchmark for living costs
🇩🇪 Germany	Generally ≤35%	Income minus expenses; SCHUFA credit score matters

Related Calculators

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Sources & Methodology

Debt-to-income ratio is total monthly debt obligations divided by gross monthly income. Qualification methods and thresholds differ by country — a fixed DTI limit in the US, GDS/TDS ratios in Canada, and affordability stress tests in the UK.

Standards and figures reviewed 2026.