What is Debt-to-Income Ratio and How Does it Impact Your Mortgage Approval & Affordability?

By James Klingele

May 5, 2025 at 10:00 AM CST

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Mortgage lenders place great emphasis on debt-to-income (DTI) ratio to determine how much house you can afford, and whether you’ll be approved for a mortgage.

What Is Debt-to-Income Ratio?

Your DTI ratio is your total monthly debt payments divided by your gross monthly income.

For example: if you earn $10,000 a month and pay $2,000 toward debt (student loans, car payments, credit cards), your DTI is 20 percent.

DTI is split into two categories:

  • Front-end DTI: Monthly income that goes to housing-related costs (mortgage, taxes, insurance). The percentage is calculated by using this formula: (housing expenses/gross monthly income) * 100.

  • Back-end DTI: Monthly income that goes to paying debt. The percentage is calculated using this formula: (total monthly debt expense/gross monthly income) * 100.

Why It Matters: A low DTI signals to lenders that you’re more likely to repay your mortgage. A high DTI suggests you’re financially stretched and therefore high risk.

Some lender guidelines for DTI:

  • Below 36%: Ideal for most loan programs.

  • 36–43%: Acceptable, especially with strong credit.

  • Above 43%: Risky, may require compensating factors or disqualify the borrower altogether.

It’s seen as ideal for most lenders that front-end DTI sits at about 28 percent, while back-end DTI doesn’t exceed 36 percent.

Improving Your DTI

Some ways to reduce your DTI and boost your mortgage eligibility:

  • Pay down existing debt. Target high-interest balances first.

  • Increase income. A side hustle, freelancing, or second job.

  • Avoid new debt. Don’t take out new loans or open credit cards.

  • Consolidate. If rates lowered since you took out the loan, refinancing existing debt.

How Different Debts Affect Affordability

All recurring debt counts toward DTI, including the following:

  • Student loans: Counted at actual monthly payment.

  • Car loans: Applying for an auto loan can cause your credit score to dip temporarily.

  • Credit cards: Only minimum monthly payments are included, but high utilization also hurts credit scores.

All these loans can impact your credit score, which in turn can make getting approved for a mortgage difficult. The more debt you carry, the less room you’ll have for a mortgage payment, limiting the size of the home you can afford.

Understanding DTI and managing it wisely can make the difference between securing a home loan or falling short. For homebuyers, keeping DTI low is not just good advice; it’s a critical part of the process.

To learn more about home financing and the buying process, visit newhomesource.com/learn.


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James Klingele

James Klingele holds a Bachelor of Science in Digital Media Innovation from Texas State University. He is a digital media specialist and content creator with a passion for storytelling in both print and digital formats. His work has included covering high-profile events like SXSW, where he contributed to content creation for global audiences. He has been a content specialist for NewHomeSource since 2024.