Debt-to-Income Ratio: The 28/36 Rule Explained
Before a lender approves your mortgage, they check one number above almost all others: your debt-to-income ratio (DTI). More than your salary or even your down payment, DTI is the single biggest factor in how much house you can borrow. Understanding the 28/36 rule — and knowing your own number before you apply — puts you miles ahead of most first-time buyers.
What Is Debt-to-Income Ratio?
Your DTI is the percentage of your gross monthly income (before taxes) that goes toward paying debts. Lenders use it to gauge whether you can comfortably handle a new mortgage payment on top of your existing obligations. A low DTI signals financial breathing room; a high one signals risk, which can mean rejection or a higher interest rate.
The 28/36 Rule
This classic guideline breaks DTI into two separate ratios that lenders evaluate together:
- Front-end (28%): No more than 28% of gross monthly income should go to housing costs — mortgage principal, interest, property tax, insurance, and HOA (together called PITI + HOA).
- Back-end (36%): No more than 36% should go to all debt combined — housing plus car loans, student loans, minimum credit card payments, and personal loans.
Example: $7,000 Gross Monthly Income
| Ratio | Multiplier | Max monthly payment |
|---|---|---|
| Front-end (28%) | 0.28 | ~$1,960 on housing |
| Back-end (36%) | 0.36 | ~$2,520 on all debt |
In this example, if your car and student loan payments already total $560, that leaves about $1,960 for housing to stay within the 36% back-end limit — which happens to match the front-end cap perfectly. When your other debts are higher, the back-end rule becomes the binding constraint.
How to Calculate Your DTI
The formula is simple. Add up all your monthly debt payments, divide by your gross (pre-tax) monthly income, and multiply by 100:
DTI = (Total monthly debt payments ÷ Gross monthly income) × 100
Example: $2,100 in monthly debt ÷ $7,000 income = 30% DTI. That's comfortably within range for most loan programs.
Remember: lenders count your future mortgage payment in this calculation, not just your current debts. They also ignore expenses like utilities, groceries, insurance premiums, and streaming subscriptions — only debt obligations count.
What DTI Do Lenders Actually Accept?
While 36% is the classic target, many real-world programs allow more:
| Loan type | Typical max back-end DTI |
|---|---|
| Conventional (Fannie/Freddie) | Up to 43%–45%, sometimes 50% with strong profile |
| FHA | Up to 50% with compensating factors |
| VA | No hard cap; ~41% guideline plus residual income test |
| USDA | Around 41%, higher with approval |
Compensating factors — a high credit score, significant cash reserves, or a large down payment — can push these limits higher. But just because you can borrow at 50% DTI doesn't mean you should; a stretched budget leaves no room for emergencies.
How to Lower Your DTI Before Applying
- Pay down credit cards and small loans. Eliminating a $300 minimum payment can meaningfully move your ratio.
- Avoid new debt before closing. No new car loans or big credit purchases — lenders re-check right before funding.
- Increase documented income. A raise, bonus, or a side stream with a track record can all count.
- Choose a less expensive home or make a larger down payment to shrink the mortgage portion.
- Pay off a car loan with few payments left — lenders may exclude debts with 10 or fewer months remaining.
Check Your Numbers
Your DTI directly determines your buying power. Model it before you shop:
- See how your DTI affects what you can borrow with the Affordability Calculator.
- Estimate your full monthly payment with the Mortgage Calculator.
Frequently Asked Questions
What is a good debt-to-income ratio for a mortgage?
A back-end DTI at or below 36% is considered strong, and many lenders prefer housing costs under 28% of gross income. Lower is always better and can help you secure a better rate.
What is the maximum DTI to qualify for a mortgage?
Conventional loans often approve up to 43–45%, and FHA loans can reach 50% with strong compensating factors like a high credit score or cash reserves. Limits vary by lender and loan program.
Does DTI use gross or net income?
DTI is calculated using gross (pre-tax) monthly income. Add up your monthly debt payments, divide by gross monthly income, and multiply by 100.
What debts are included in DTI?
Lenders count the future mortgage payment, plus car loans, student loans, minimum credit card payments, personal loans, and child support or alimony. Utilities, groceries, and other living expenses are not included.
How can I lower my DTI quickly?
Pay down credit card balances and small loans, avoid taking on any new debt before closing, document additional income, or consider a less expensive home with a larger down payment.