Credit & Qualifying

What is a debt-to-income ratio and why does it matter?

Updated Jul 1, 2026

The short answer

Your debt-to-income ratio (DTI) is your total monthly debt payments divided by your gross monthly income, expressed as a percentage. Lenders use it to judge whether you can afford a new mortgage payment. Many follow a rough guideline where housing costs stay near 28% of gross income and total debts near 36%, though limits vary by loan program. A lower DTI generally improves your approval odds and terms.

Key points

  • DTI = monthly debt payments ÷ gross monthly income.
  • Common guideline: ~28% housing, ~36% total debt.
  • Limits vary by loan type and lender.
  • Lower DTI improves approval odds and pricing.

Front-end vs. back-end

The front-end ratio counts only housing costs; the back-end ratio counts all recurring debt including the mortgage. Lenders look at both. CandidCost’s Affordability Calculator builds a DTI worksheet so you can see your numbers.

Put this to work

Sources

Every claim above traces to a public government source.

  • T1What is a debt-to-income ratio?

    Consumer Financial Protection Bureau · Government / primary · 2024

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