Debt-to-Income Ratio (DTI)
The percentage of your gross monthly income that goes toward debt payments, including the proposed mortgage — one of the most important numbers in any loan approval.
What DTI Is
Your debt-to-income ratio (DTI) is the share of your gross monthly income consumed by debt payments. Lenders use it to gauge how much room you have to take on a mortgage. The lower your DTI, the more comfortably you can afford the payment — and the easier you are to approve.
There are two versions:
- Front-end (housing) DTI — just the proposed mortgage payment (principal, interest, taxes, insurance, and any HOA) divided by gross income.
- Back-end (total) DTI — the mortgage plus all other monthly debts (car loans, student loans, credit-card minimums, etc.). This is the number lenders weigh most.
A Worked Micro-Example
Suppose your qualifying income is $10,000/month. You have a $400 car payment and $200 in credit-card minimums, and the home you want carries a $2,400/month payment.
- Back-end DTI = ($2,400 + $400 + $200) ÷ $10,000 = 30%.
If your qualifying income were instead $8,000/month, that same debt load pushes your DTI to 37.5% — and a larger mortgage could push you past a lender's comfort threshold. This is exactly why the self-employed care so much about add-backs and program choice: anything that raises qualifying income directly lowers DTI.
Why DTI Matters for the Self-Employed
DTI is where the gross-vs-net income problem hits hardest. Conventional lenders generally prefer back-end DTIs at or below the mid-40s, with flexibility for strong files; the CFPB's Qualified Mortgage standards historically anchored around a 43% threshold, though non-QM loans can go higher when other strengths offset the risk. Self-employed borrowers often look worse on DTI than they really are because their write-offs shrink the income side of the ratio.
Two levers move your DTI:
- Raise qualifying income — choose the program (bank statement, 1099, asset depletion) that counts the most of your real cash flow.
- Lower the debt side — pay off or pay down installment loans and revolving balances before applying.
The Practical Lesson
Run your DTI before you shop, using a realistic qualifying-income figure for the program you'll use — not your gross revenue and not your skinny tax-return net. A self-employed borrower who clears a credit-card balance and picks the right income program can drop their DTI several points, which often means a bigger approval, a better rate, or both. Strong reserves and a low loan-to-value can also persuade a lender to accept a higher DTI.
Apply This Concept
Related Terms
Qualifying Income
The income figure a lender actually uses to approve your loan and calculate your debt-to-income ratio — which, for the self-employed, is rarely the same as either your gross revenue or your gross pay.
Loan-to-Value (LTV)
The ratio of your loan amount to the property's value, expressed as a percentage — a key measure of risk that drives down payment requirements, interest rates, and whether mortgage insurance applies.
Reserves
Liquid assets you must have left over after closing — measured in months of mortgage payments — that prove to a lender you can keep paying if income dips.
Add-Backs
Non-cash or non-recurring deductions a lender adds back to your net profit when calculating qualifying income — because they lowered your taxable income without actually reducing your cash flow.
Gross vs. Net Income
The distinction between what a business takes in (gross) and what remains after expenses (net) — the gap that explains why self-employed borrowers often look poorer to lenders than they really are.
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