Debt-to-Income Ratio: The Number That Determines Whether You Qualify for a Mortgage
When you apply for a mortgage, one of the first numbers a lender calculates is your debt-to-income ratio, or DTI. It's a simple percentage that tells the lender whether your income can comfortably support your existing debts plus a new mortgage payment. A high DTI can disqualify you from a loan — even if your credit score is excellent.
Use our DTI Calculator to find out where you stand.
How DTI Is Calculated
Your DTI is the sum of all your monthly debt payments divided by your gross monthly income (before taxes).
For example: your gross monthly income is $7,000. Your monthly debts include a $450 car payment, $200 student loan, and $150 minimum credit card payment. Your total monthly debt is $800.
DTI = $800 / $7,000 = 11.4%
The Two DTI Numbers Lenders Look At
Lenders calculate two ratios, called the front-end ratio and the back-end ratio.
| Ratio | Formula | What It Includes | Typical Max |
|---|---|---|---|
| Front-End DTI | Housing costs / Gross income | Rent or mortgage only | 28% |
| Back-End DTI | Total debt / Gross income | Housing + car + student loans + credit cards + child support | 43% |
The back-end ratio is the one that matters most. It's the number mortgage underwriters focus on when making approval decisions.
DTI Thresholds by Loan Type
| Loan Type | Maximum DTI | Notes |
|---|---|---|
| Conventional | 43% | Some programs allow up to 50% with compensating factors |
| FHA | 50% | Manual underwriting required above 43% |
| VA | No hard limit | Compensating factors considered; 43% is a common guideline |
| USDA | 43% | 29% front-end ratio also evaluated |
| Jumbo | 45% | Stricter standards; often requires 36% or below |
The 28/36 Rule
The traditional 28/36 rule is a benchmark many lenders use as a soft guideline: no more than 28% of gross income on housing costs and no more than 36% on total debt. While many loan programs allow higher ratios, staying within 28/36 puts you in the safest approval territory.
How to Lower Your DTI
There are two levers: increase your income and decrease your debt. Here are practical strategies for each.
- Pay off existing debt before applying. Eliminating a $5,000 car loan or paying down a student loan reduces your monthly obligations.
- Don't take on new debt while house hunting. Buying a car or opening a new credit card right before applying can push you over the limit.
- Request rent as housing expense. If you rent, some lenders accept your actual rent rather than the area median rent, which can lower your front-end DTI.
- Add a bonus or commission to your qualifying income. If you can document consistent bonus income for two years, lenders may include it in your gross income calculation.
- Make a larger down payment. A bigger down payment reduces your monthly mortgage payment, which directly lowers your DTI.
Compensating Factors That Can Override a High DTI
If your DTI is above the standard threshold, lenders may still approve you if you have compensating factors that reduce their risk.
- Excellent credit score (740+) — proves you're a reliable borrower
- Significant cash reserves — 6+ months of mortgage payments in savings
- Large down payment (20%+) — reduces the loan-to-value ratio
- Low housing expense ratio — even if total DTI is high, a low front-end ratio is a positive signal
- Stable employment history — 2+ years in the same field reduces income risk
DTI vs Other Key Metrics
DTI is just one of several numbers lenders evaluate. It works alongside credit score, loan-to-value ratio, and debt-to-asset ratio to paint a complete picture of your financial health.
| Metric | What It Measures | Ideal Range | Weight in Decision |
|---|---|---|---|
| Credit Score | Payment reliability | 740+ | Very High |
| DTI | Income vs debt burden | Below 36% | Very High |
| Loan-to-Value | Down payment size | 80% or below | High |
| Debt-to-Asset | Wealth vs obligations | Below 100% | Medium |
Use our DTI Calculator to check your numbers, and our Mortgage Affordability Calculator to find the right home price for your situation.