What DTI measures and why lenders care
Debt-to-income compares your required monthly debt payments to your gross monthly income. It is the single most predictive underwriting metric for mortgage default risk, which is why it can override a good credit score. There are two versions: the front-end ratio counts only the housing payment, and the back-end ratio counts all debt obligations. Underwriters look primarily at the back-end number.
The benchmarks
- Under 36% — comfortable, approvals are routine, best pricing.
- 36–43% — acceptable at most lenders; 43% is the long-standing qualified mortgage threshold.
- 43–50% — possible with compensating factors, FHA programs, or manual underwriting. Expect more documentation.
- Over 50% — very difficult for a conforming mortgage.
Gross, not net
DTI uses income before taxes and deductions. That makes the ratio look better than your lived cash flow, which is exactly why a "qualified" payment can still feel unaffordable. Run a second calculation using take-home pay to see the number that will actually govern your month.
What counts, what does not
Included: mortgage or rent, HOA dues, property tax and insurance if escrowed, auto loans and leases, student loans (using the actual or an imputed payment for deferred loans), minimum credit card payments, personal and instalment loans, and court-ordered alimony or child support. Excluded: utilities, phone, groceries, insurance premiums not tied to the mortgage, streaming subscriptions and other discretionary spending.
How to improve the ratio before applying
Retiring a whole payment beats shaving balances. If you have a car loan with eight payments left, clearing it removes the full payment from the calculation. Paying down a credit card lowers the minimum only slightly. Increasing documented income — a raise, a second job with a two-year history, or documented bonus income — works on the other side of the fraction. And avoid any new credit in the 90 days before applying; a new car payment has sunk more mortgage approvals than almost anything else.