Debt-to-Income Ratio Explained: Front-End, Back-End, and the 28/36 Rule

What debt-to-income measures

Debt-to-income (DTI) compares your required monthly debt payments with your gross monthly income. Lenders use it as a quick stress test: if too much of each paycheck is already spoken for, a new mortgage payment is harder to carry—even when the home itself looks affordable on paper.

Front-end vs back-end DTI

Front-end DTI looks at housing costs alone—often rent or PITI. A common guideline target is about 28% of gross monthly income.

Back-end DTI adds other monthly debts such as auto loans, student loans, personal loans, and minimum credit card payments. A common guideline target is about 36%. Many borrowers fail the back-end test first because non-housing debts shrink the remaining budget.

How to lower a high DTI

• Pay down or refinance high monthly installment debts.
• Avoid new car loans or large financed purchases before applying.
• Raise documented income where legitimate and stable.
• Choose a lower housing payment via price, rate, term, taxes, or insurance.

Check your current ratios in the DTI calculator, then translate a healthier payment budget into a purchase price with the affordability calculator.

Guidelines are not guarantees

Loan programs differ. Some allow higher DTI with strong credit, reserves, or other compensating factors. Treat 28/36 as a planning fence, confirm program rules with a lender, and leave room for real-life costs that never appear on a DTI worksheet.