DTI stands for Debt-to-Income ratio. It's one of the most important numbers in your mortgage application — and one most people have never heard of until they're already in the process.
What DTI actually means
DTI is the percentage of your gross monthly income that goes toward monthly debt payments. There are two versions lenders look at:
- Front-end DTI: Just your housing payment (P&I + taxes + insurance + HOA + PMI) divided by gross monthly income.
- Back-end DTI: All monthly debts (housing + car payments + student loans + credit card minimums + any other installment debt) divided by gross monthly income.
Illustration: $6,000 gross qualifying monthly income, $1,800 complete housing payment and $400 other qualifying monthly debt. Back-end DTI = ($1,800 + $400) ÷ $6,000 = 36.6667%, displayed 36.7%. This ratio alone is not a loan approval.
DTI limits by loan type
- Fannie Mae conventional: Manual underwriting generally uses 36% maximum, up to 45% with specified credit/reserves; DU permits up to 50%. Exceptions and lender overlays apply. These are not universal conventional limits.
- FHA: Manual and automated underwriting have different requirements. A high DTI requires the applicable findings and conditions; 57% is not a universal allowance justified simply by compensating factors.
- VA: 41% is a guideline, with residual-income analysis and other underwriting conditions. Being below it does not guarantee approval; exceeding it is not an automatic denial.
- USDA Guaranteed: Published ratio guidance and automated underwriting findings must be applied to the actual transaction. Check housing and total-debt ratios separately.
How to lower your DTI
Qualifying income and counted debts follow program rules. Paying down a balance helps DTI only if it reduces the qualifying monthly obligation. A co-borrower adds eligible income and their counted debts; the combined ratio may rise or fall.
DTI limits vary by lender and loan program. A licensed loan officer can help you understand your specific qualifying ratios.