How Debt-to-Income Ratio Works
DTI compares recurring monthly debt obligations with gross monthly income. Front-end DTI focuses on proposed housing costs. Back-end DTI adds other recurring debts such as car loans, student loans, credit-card minimums, and other required payments.
There is no single approval cutoff that applies to every mortgage. For example, Fannie Mae's conventional guidance distinguishes manual underwriting from Desktop Underwriter (DU) casefiles and can permit higher ratios in some automated cases. Government-backed programs use their own rules.
Reference, not an approval decision
Use this calculator to understand the ratio. Your lender's underwriting system determines whether the full application qualifies.
28/36 Rule Calculator: What the Rule Means
The 28/36 rule is a budgeting rule of thumb, not a universal mortgage-approval standard. The traditional shorthand compares housing costs with about 28% of gross monthly income and total recurring debt with about 36% of gross monthly income. Actual underwriting can use different limits and additional risk factors.
This calculator already shows the two ratios needed to compare your numbers: front-end DTI for proposed housing costs and back-end DTI for housing plus other recurring debts. For a broader affordability check, see our guide to the 28/36 rule and home affordability.
If your housing estimate includes mortgage insurance, read what PMI is and how a monthly PMI payment is estimated before entering that amount.