What is debt-to-income ratio?

What Are the Two Types of DTI?

Lenders calculate two versions of DTI:

• Front-end DTI (housing ratio): Only your housing costs (mortgage principal + interest + property taxes + insurance + HOA dues, if any) divided by gross monthly income. Conventional guidelines suggest this should stay below 28%.
• Back-end DTI (total debt ratio): All monthly debt obligations (housing costs + credit card minimums + auto loans + student loans + personal loans + child support) divided by gross monthly income. This is the figure most lenders focus on. Conventional guidelines suggest below 36%.

For example, if your gross monthly income is $6,000 and your total monthly debts are $2,400, your back-end DTI is 40% ($2,400 ÷ $6,000). This 40% ratio is above Fannie Mae's usual 36% limit for loans reviewed manually, but could still qualify for a conventional or FHA loan if the other requirements are met.

How Does DTI Affect Mortgage Qualification?

DTI is one of the most important factors in mortgage underwriting. Different loan programs have different thresholds:

• Conventional (Fannie Mae/Freddie Mac): Generally capped at 45% back-end DTI, with automated underwriting systems sometimes approving up to 50% with strong compensating factors (high credit score, significant reserves)
• FHA: FHA's limits depend on how the loan is underwritten. In manual underwriting, scores of 500-579 are limited to 31% housing and 43% total debt ratios, and scores of 580 or higher can go up to 40% and 50% with two documented compensating factors such as cash reserves or residual income.
• VA: No hard DTI cap, but uses a "residual income" test that ensures veterans have enough income left after all debts and living expenses. In practice, VA loans above 41% DTI receive extra scrutiny.
• USDA: 41% back-end DTI limit, with limited flexibility for compensating factors.
• Qualified Mortgage (QM): Under the CFPB's Ability-to-Repay rule, QMs that aren't higher-priced and seasoned QMs receive a legal safe harbor. Higher-priced QMs that aren't seasoned generally receive a presumption that the lender met the repayment rules, which borrowers can challenge. The general Qualified Mortgage (QM) definition has had no DTI cap since the CFPB's 2021 amendments, which replaced it with price-based thresholds.

Why Does High DTI Lead to Default?

A high DTI ratio means a borrower has very little room between their income and their obligations. When an unexpected expense occurs — medical bill, car repair, job loss — there's no buffer to absorb the shock. This is exactly what the American Distress Index's Debt Burden domain measures at a macro level.

The national household debt service ratio (all household debt payments as a percentage of disposable income) was 11.11% in Q2 2026. A national average hides wide variation:

• FHA borrowers tend to have higher DTIs at origination; 13.64% of FHA loans in HUD's monthly report were at least one payment behind in August 2026
• Borrowers who purchased or refinanced at 2020-2021 low rates are "locked in" — selling or refinancing at today's higher rates would increase their DTI
• Rising insurance costs, property taxes, and HOA dues increase the front-end DTI over time even when the mortgage payment itself stays fixed

The ADI tracks this squeeze through the debt service ratio, the single member of its Debt Burden domain. The mortgage debt service ratio and FHA delinquency are contextual evidence of the same household squeeze the ADI captures through the debt service ratio and through the mortgage, credit-card, consumer-loan, and auto-loan delinquency members of its Delinquency domain.

How Can You Lower Your DTI?

To improve your DTI before or during homeownership:

• Pay down revolving debt: Reducing credit card balances has the fastest DTI impact because it eliminates monthly minimum payments
• Avoid new debt: New auto loans, credit cards, or personal loans increase your monthly obligations
• Increase income: Any documented income increase lowers the ratio (the denominator grows)
• Refinance at a lower rate: If available, refinancing can lower the housing portion of DTI — though current high rates make this difficult for recent buyers
• Extend loan terms: Consolidating or extending repayment terms lowers monthly payments but increases total interest cost