DTI explained.

Debt-to-income ratio is the single most underrated number in loan approval. A borrower with an 800 credit score and a 55% DTI will be denied for a conventional mortgage. A borrower with a 680 score and a 28% DTI will sail through. Here's exactly how DTI works and how to game it — legally — in your favor.

Front-end vs. back-end DTI

Mortgage underwriters calculate two ratios:

• Front-end DTI: just your proposed housing payment (principal, interest, taxes, insurance, HOA) divided by gross income.
• Back-end DTI: all monthly debt obligations — housing, car, student loans, credit card minimums, personal loans — divided by gross income.

The traditional "28/36 rule" caps front-end at 28% and back-end at 36%, though modern guidelines flex up to 45–50% with compensating factors.

What counts as "debt" in DTI

Included:

• Mortgage or rent payment
• Auto loan payments
• Student loan payments (even deferred — lenders use 1% of balance or amortized payment)
• Minimum credit card payments
• Personal loan payments
• Child support and alimony
• Co-signed loans (yes, even if someone else is paying)

Not included:

• Utilities, insurance (unless bundled in mortgage escrow)
• Groceries, gas, entertainment
• Taxes withheld from paycheck
• 401(k) contributions

What counts as "income"

Gross income, meaning before taxes. For W-2 employees, this is straightforward. Self-employed income is averaged over the last 2 years of tax returns. Non-taxable income (disability, some social security) can sometimes be "grossed up" by 15–25% for qualification purposes.

DTI thresholds by loan type

Three ways to lower your DTI quickly

1. Pay off the smallest balances first. Eliminating a $120/month car payment has the same DTI impact as earning more — but faster.
2. Refinance to a longer term. Controversial, but lower monthly payments = lower DTI. The tradeoff is more interest over time.
3. Document additional income. Bonuses, side income, and part-time work count — if you can document them with 1–2 years of history.

Three ways to raise your DTI without realizing it

• Opening a new credit card before applying. Minimum payment counts immediately.
• Buying a car before the mortgage. Adding $400/month in car debt just before applying for a mortgage can disqualify you.
• Co-signing a loan. The full payment counts against your DTI, even if you never see the bill.

When DTI isn't everything

Some lenders prioritize "residual income" — what's left after all obligations — over DTI. VA loans famously do this. A borrower with high income and high DTI may still have plenty of residual income, and vice versa. If you're a VA borrower, understand both metrics.

Action step

Run your DTI right now with our free calculator. Know the number before a lender does.

Last reviewed: January 2026