Housing Ratio (Front-End DTI)

The housing ratio — also called the front-end debt-to-income ratio or housing expense ratio — is the percentage of a borrower's gross monthly income consumed by housing expenses. For a new mortgage: housing ratio = monthly PITI (Principal + Interest + Taxes + Insurance) ÷ gross monthly income × 100. For lenders, this ratio indicates how affordable the proposed mortgage is relative to income, before accounting for other debts. Example: $2,200 monthly PITI on $6,500 gross monthly income = 33.8% housing ratio. Most conventional lenders target ≤28%; FHA and VA allow up to 31%; USDA up to 29%. The housing ratio is always analyzed alongside the back-end DTI (which includes all debts). See debt-to-income ratio (back-end DTI) for the complete picture. The CFPB DTI guide covers both front-end and back-end ratios.

PITI stands for Principal, Interest, Taxes, and Insurance — the four components of a typical monthly mortgage payment: (1) Principal: The portion of your payment reducing the loan balance; (2) Interest: The cost of borrowing — the interest portion of the monthly payment; (3) Taxes: Property taxes, typically escrowed and paid monthly (1/12 of annual property tax bill); (4) Insurance: Homeowner's insurance premium, escrowed and paid monthly. Additional amounts included in the housing ratio: (5) PMI/MIP: Private mortgage insurance (conventional) or mortgage insurance premium (FHA) if applicable; (6) HOA dues: If the property is a condo or in an HOA — monthly dues are included; (7) Flood insurance: Required by lender in flood zones. All of these together are sometimes called "PITIA" (adding Association dues). See PITI glossary entry for full definition and CFPB home buying preparation guide.

Housing ratio (front-end DTI) limits by loan type: (1) Conventional (Fannie Mae / Freddie Mac): No hard front-end limit in guidelines — the automated underwriting system (DU/LP) approves holistically. In practice, lenders target ≤28–31% for manual underwriting; (2) FHA: Front-end limit of 31%; back-end limit of 43% (flexible with compensating factors). AUS may approve higher; (3) VA: No official front-end ratio limit; focus is on the residual income test (leftover income after all obligations). Back-end DTI of 41% is a guideline; (4) USDA: Front-end limit of 29%; back-end limit of 41% (waivable with certain compensating factors); (5) Canada — GDS (Gross Debt Service ratio): The Canadian equivalent of front-end DTI. Maximum 39% for insured mortgages (CMHC). Includes: mortgage P+I + property taxes + heating costs + 50% of condo fees. See Canada GDS/TDS ratio and CFPB DTI explanation.

Housing ratio calculation: Step 1 — Calculate monthly PITI+. Principal + Interest: use the mortgage calculator for your loan amount, rate, and term. Property taxes: find the annual tax bill for the home and divide by 12. Homeowner's insurance: typically $100–$200/month for a median home. PMI (if applicable): typically 0.2–1.5% of loan amount ÷ 12. HOA dues: listed in the listing details. Step 2 — Divide by gross monthly income: use pre-tax, pre-deduction income. If self-employed, use the 2-year average from tax returns (same as lender calculation). Step 3 — Multiply by 100 for percentage. Example: P+I $1,800 + taxes $400 + insurance $150 + PMI $150 = $2,500 PITI. Gross income $7,500/month. Housing ratio = $2,500/$7,500 = 33.3%. This is on the upper end for conventional but within FHA limits. To lower: increase income documentation, increase down payment (reduces P+I and eliminates PMI), or select a lower-priced property.

Canada's Gross Debt Service (GDS) ratio is the Canadian equivalent of the US front-end DTI but with slightly different inclusions: GDS = (Monthly mortgage P+I + property taxes + heating costs + 50% of condo fees) ÷ gross monthly income. The US front-end DTI typically excludes heating costs. Canadian GDS maximum under CMHC insurance guidelines: 39% (as of 2025). For uninsured mortgages, lenders may allow slightly higher GDS with compensating factors. Canada also uses the Total Debt Service (TDS) ratio (equivalent to US back-end DTI) — includes all GDS components plus all other monthly debt obligations. TDS maximum: 44% for insured mortgages. Stress test: both GDS and TDS must pass at the qualifying rate (greater of 5.25% or contract rate + 2%), not just the contract rate. This is why some buyers qualify on the contract rate but fail the stress test. See Canada GDS/TDS ratio glossary, stress test glossary, and the OSFI B-20 guideline.

Six ways to reduce your housing ratio: (1) Increase gross income: Adding a co-borrower's income, documenting rental income, bonus or part-time income (if 2-year history exists), or requesting a raise before applying; (2) Increase down payment: Larger down payment reduces the loan amount → reduces P+I → reduces ratio; (3) Eliminate PMI: 20% down removes PMI entirely — significant reduction; (4) Choose a lower-priced property: Directly reduces PITI; (5) Find lower property taxes: Some areas have significantly lower tax rates than others — a factor worth researching; (6) Extend amortization: A 30-year mortgage has lower P+I than a 15-year for the same balance (but costs more in total interest). Note: improving the housing ratio is often about income documentation — lenders use documented qualifying income, which may differ from actual income. Work with a mortgage broker to optimize income presentation within legal documentation requirements. See how to calculate mortgage affordability and the CFPB home affordability guide.