What Is DTI and Why Lenders Use It
Your debt-to-income ratio (DTI) is the percentage of your gross monthly income that goes toward monthly debt payments. Lenders use it as a key measure of your ability to manage monthly payments and repay debts.
DTI is different from your credit score: your score measures creditworthiness (how reliably you pay), while DTI measures capacity (whether you have enough income to take on more debt). You can have an excellent credit score but be declined for a mortgage because your DTI is too high.
Two Types of DTI
Front-End DTI (Housing Ratio)
Only housing costs ÷ gross monthly income.
Includes: mortgage P&I + property taxes + homeowners insurance + PMI + HOA fees
Front-end DTI = total housing costs ÷ gross monthly income
Conventional loan guideline: typically 28% or less (though up to 36% may be acceptable with strong compensating factors)
Back-End DTI (Total Debt Ratio)
All debt payments ÷ gross monthly income.
Includes: housing costs PLUS all minimum debt payments (car loans, student loans, credit cards, personal loans, child support/alimony)
Back-end DTI = all monthly debt payments ÷ gross monthly income
This is typically what lenders mean when they refer to "DTI" without specifying.
Lender Thresholds by Loan Type
| Loan Type | Front-End Max | Back-End Max | Notes |
|---|---|---|---|
| Conventional (standard) | 28% | 43% | Fannie/Freddie guidelines |
| Conventional (with compensating factors) | — | 45–50% | High reserves, excellent credit |
| FHA loan | 31% | 43–50% | More flexible; mortgage insurance required |
| VA loan | — | 41% | No front-end limit; residual income also evaluated |
| Preferred / ideal | ≤28% | ≤36% | Best rates and approval odds |
Worked Example
Monthly gross income: $8,000
Monthly debts:
- Proposed mortgage PITI: $2,000
- Car loan: $450
- Student loan minimum: $300
- Credit card minimum: $100
- Total: $2,850
Front-end DTI: $2,000 ÷ $8,000 = 25% (good)
Back-end DTI: $2,850 ÷ $8,000 = 35.6% (good)
This borrower would likely be approved for a conventional mortgage at competitive rates.
Important: Gross vs. Net Income
DTI always uses gross income (before taxes), not take-home (net) income. This means your actual cash flow may feel tighter than your DTI suggests, since you're paying 20–30% in taxes before you see your paycheck.
A 36% back-end DTI using gross income might mean 50%+ of your take-home pay goes to debt — something to factor into your real-world budgeting.
How to Improve DTI Before Applying
- Pay off revolving debt (credit cards): Paying off a card eliminates the minimum payment from your DTI calculation
- Pay off installment debt near payoff: If you have a car loan with 10 months remaining, paying it off removes that payment from DTI
- Avoid taking on new debt in the months before applying for a mortgage
- Increase income: A raise, second job, or documented side income can lower your DTI ratio
- Consider a smaller loan amount: A lower purchase price or larger down payment reduces your housing cost and front-end DTI
Use our CalcPeek financial calculators to calculate your DTI and model how different scenarios affect your qualifying ratios.