Debt-to-Income Ratio: What It Is & How Lenders Use It

What Is Debt-to-Income Ratio?

Your debt-to-income ratio (DTI) is the percentage of your gross monthly income that goes toward paying monthly debt obligations. Lenders use it as one of the primary underwriting criteria for mortgages, personal loans, auto loans, and other credit products. A lower DTI signals that you have breathing room between what you earn and what you owe — making you a lower-risk borrower.

According to the Federal Reserve’s Household Debt Service and Financial Obligations Ratios data, the household debt service ratio (mortgage and consumer debt payments as a share of disposable income) has historically ranged between 9% and 13%. At its peak before the 2008 financial crisis, it reached nearly 13%. By 2023, it had settled closer to 9.8% as households paid down debt during the pandemic savings boom. Total U.S. household debt hit $17.5 trillion in Q4 2023, per the Federal Reserve Bank of New York.

The DTI Formula

DTI = (Total Monthly Debt Payments ÷ Gross Monthly Income) × 100

Gross monthly income is your pre-tax income from all sources: salary, wages, bonuses, commissions, rental income, alimony received, and documented investment income. Self-employed borrowers typically use a two-year average of net business income from tax returns.

Total monthly debt paymentsinclude every recurring debt obligation you carry — but not all monthly expenses.

What Counts in DTI — and What Doesn't

The CFPB is explicit: DTI includes only legally obligated debt payments, not living expenses. Lenders verify these obligations against your credit report and loan statements.

Front-End vs Back-End DTI

Mortgage lenders evaluate two separate DTI ratios. Understanding both matters when you’re preparing to apply.

The traditional “28/36 rule” says housing costs should stay below 28% of gross income and all debt should stay below 36%. But this is a guideline, not a hard rule — many lenders approve at higher ratios, especially with strong credit scores or large down payments.

DTI Thresholds by Lender Standard

Fannie Mae’s Selling Guide (updated 2024) allows Desktop Underwriter to approve loans with DTIs above 45% when compensating factors are present — such as a FICO score above 720, 12 months of cash reserves, or a significant down payment. The CFPB’s Qualified Mortgage (QM) rule, revised in 2021, moved away from a strict 43% DTI cap for QM loans backed by Fannie/Freddie, giving lenders more flexibility.

DTI Requirements by Loan Type

5 Debts That Hurt Your DTI Most

Not all debts damage your DTI equally. These five have the biggest impact because of their size or minimum payment structure:

• Auto loans: A $35,000 car at 7% over 60 months = $693/month. That alone consumes 11.5% of a $6,000/month gross income before anything else is counted.
• Student loans: The average federal student loan payment is $503/month (Federal Reserve Bank of New York, 2023). On income-driven repayment, the payment may be lower — but lenders often use 1% of the outstanding balance per month if the loan is deferred.
• Credit card minimum payments: A $10,000 balance with a 2% minimum = $200/month. Paying only minimums keeps this drag on your DTI for years.
• Personal loans: Fixed monthly payments with no flexibility. A $15,000 personal loan at 12% over 36 months = $498/month.
• Co-signed debt: If you co-signed a loan for someone else, lenders count that full payment against your DTI — even if the primary borrower makes every payment on time.

How to Calculate Your DTI: A Step-by-Step Example

Step 1: Add Up All Monthly Debt Payments

• Mortgage / rent: $1,500
• Car loan: $350
• Student loans: $300
• Credit card minimums: $150
• Personal loan: $100
• Total monthly debt: $2,400

Step 2: Determine Gross Monthly Income

• Salary: $6,250 ($75,000/year)
• Side income: $500
• Total gross monthly income: $6,750

Step 3: Divide and Multiply

DTI = $2,400 ÷ $6,750 × 100 = 35.6%

This DTI falls in the “acceptable” range and would qualify for most conventional mortgages. Front-end DTI (housing only) = $1,500 ÷ $6,750 = 22.2%— well within the 28% target.

How to Lower Your DTI Before Applying

There are two levers: reduce debt payments or increase income. Ideally, do both — but focus on the lever that moves faster for your situation.

Reduce Debt Payments

• Pay off credit cards first: Eliminating a $150/month minimum drops your DTI by 2.2 percentage points on a $6,750 income. Cards have the worst interest rates (20–29% APR average, 2024) and eliminating them helps your credit utilization too.
• Pay off a car loan: A $350/month payment eliminated = 5.2 percentage point DTI drop at $6,750 income. If you’re within 12 months of payoff, this is worth prioritizing before a mortgage application.
• Refinance student loans: Extending the repayment term lowers the monthly payment (though it increases total interest paid). For DTI purposes, a lower payment is what the lender sees.
• Consolidate debt: Rolling multiple high-payment debts into one lower-payment personal loan can reduce total monthly obligations — but compare the new monthly payment carefully.
• Avoid new debt: Any new loan or credit card opened before a mortgage application can hurt your DTI and trigger a hard inquiry that dips your credit score.

Increase Gross Income

• Negotiate a raise: A $5,000 annual raise adds $417/month to gross income, dropping a 35.6% DTI to about 33.5% in our example above.
• Document freelance income: Lenders typically require two years of self-employment tax returns to count freelance income. Start the paper trail early.
• Add a co-borrower: A spouse or partner’s income is included in the DTI calculation for joint applications — their debt payments are included too, so run the numbers both ways.

How DTI Relates to Your Credit Score

DTI and credit score are separate metrics, but lenders evaluate them together. Your credit score is not affected by your DTI — it’s driven by payment history, credit utilization, age of accounts, and credit mix. However, the same habits that hurt your DTI (carrying high balances, opening new debt) also hurt your credit score.

When lenders evaluate a mortgage application, they look at both simultaneously. A borrower with a 750 FICO score and 42% DTI may get approved where a borrower with 680 FICO and 40% DTI might not — because the higher score signals lower default risk and can offset the elevated DTI. According to the CFPB’s 2023 Consumer Credit Report, borrowers with DTIs above 43% had mortgage delinquency rates roughly 2.5× higher than those with DTIs below 36%.

Related Guides

• How Much House Can I Afford? — uses DTI, income, and savings to estimate your homebuying budget
• Snowball vs Avalanche: Which Debt Payoff Strategy Is Right for You? — tactical plans to eliminate debt faster
• Amortization Explained — understand how monthly mortgage payments are split between principal and interest
• How to Calculate Self-Employment Tax — income for self-employed borrowers is counted differently by mortgage lenders

Frequently Asked Questions

What is a good debt-to-income ratio?

A DTI of 36% or lower is considered good by most lenders. Under 28% is excellent. For mortgage qualification, most conventional lenders allow a maximum back-end DTI of 43%, though Fannie Mae and Freddie Mac may approve up to 50% with strong compensating factors via Desktop Underwriter. The lower your DTI, the better your chances of loan approval and favorable interest rates.

How is DTI calculated?

DTI = (Total Monthly Debt Payments ÷ Gross Monthly Income) × 100. Add all monthly debt obligations — mortgage or rent, auto loans, student loans, credit card minimum payments, personal loans — then divide by your gross (pre-tax) monthly income and multiply by 100. Example: $2,000 in monthly debt payments ÷ $6,000 gross monthly income = 33.3% DTI.

What DTI do I need to qualify for a mortgage?

For conventional loans backed by Fannie Mae or Freddie Mac, the standard maximum back-end DTI is 43–45%, though Desktop Underwriter approval can extend to 50% with compensating factors. FHA loans (HUD Handbook 4000.1) allow up to 50% back-end DTI with strong credit. VA loans use a 41% guideline but apply a residual income test. USDA loans cap at 41%. Requirements vary by lender and individual file strength.

Does rent count in DTI?

Yes — your current rent is included in your back-end DTI because it’s a recurring monthly obligation. When you apply for a mortgage, lenders replace your rent with the projected new mortgage payment (PITI: principal, interest, taxes, insurance). If you plan to rent out your current home, lenders may count rental income to offset that payment, depending on documentation.

How can I lower my debt-to-income ratio?

Two levers: reduce debt payments or increase income. To reduce debt: pay off credit cards (highest impact per dollar eliminated), pay off a car loan, consolidate high-interest debt into lower monthly payments, and avoid new debt before applying. To increase income: negotiate a raise, document freelance income with two years of tax returns, or add a co-borrower to the application. Eliminating a $300/month car payment drops DTI by 5 percentage points on a $6,000/month gross income.