# Debt-to-Income Ratio: What Lenders Actually See
Credit scores measure how reliably you repay debt. Debt-to-income ratio (DTI) measures whether you have enough income to take on more. Lenders use both — but DTI is the hard cap. A perfect credit score does not overcome a DTI above lender thresholds.
How DTI is calculated
DTI is total monthly debt payments divided by gross monthly income, expressed as a percentage.
**Monthly debt payments** include: minimum credit card payments, auto loan payments, student loan payments, mortgage or rent (for the new obligation), personal loans, child support or alimony. Note: utilities, insurance, groceries, and subscriptions do not count.
**Gross income** is pre-tax income from all sources: salary, freelance, rental income, investment income.
A person earning $8,000/month with $2,400 in monthly debt obligations has a DTI of 30%.
The thresholds that matter
Lenders use two DTI calculations for mortgages:
**Front-end DTI** (housing ratio): proposed housing payment only ÷ gross income. Most conventional lenders prefer under 28%.
**Back-end DTI** (total debt ratio): all monthly debt payments ÷ gross income. This is the more important number: - Under 36%: Strong — most lenders approve - 36–43%: Acceptable — most conventional loans still available - 43–50%: Restricted — FHA may approve; conventional lenders often decline - Above 50%: Most lenders decline regardless of credit score
Debt-to-Income (DTI) Calculator
Front-end (housing only) and back-end (housing + all other debt) ratios — what mortgage underwriters actually look at.
Tight — exceeds the conventional 36% preferred ceiling but within FHA 43% bounds.
Monthly income: ~$6,650 · Total debt: ~$2,650/mo
Educational illustration — not financial advice. Math: @/lib/finance/mortgage.ts. Guideline ratios reflect Fannie Mae / Freddie Mac / FHA published thresholds; lender-specific limits vary.
Why DTI matters more than people expect
A borrower can have an 800 credit score and be declined for a mortgage because their DTI is 52%. The credit score says they always pay — the DTI says they are already stretched. Lenders care about both questions.
Conversely, a borrower with a 680 score and a 28% DTI is a much more attractive lending risk than the inverse suggests. The DTI gives lenders confidence that monthly payments are sustainable.
The fastest ways to improve DTI
**Pay off smaller debt balances entirely.** Eliminating a $4,000 auto loan with an $280/month payment reduces your monthly debt obligations — and thus your DTI — immediately. The effect on DTI is often larger than paying down a credit card balance by the same amount, because card minimums are calculated on the balance and fall as the balance falls.
**Increase income.** DTI responds linearly to income. A side income of $1,000/month changes the calculation for someone already near a threshold.
**Avoid new debt before applying.** Each new loan or credit inquiry can temporarily affect DTI and score. Do not finance a car in the six months before a mortgage application.
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*Related: [Credit utilization](./credit-utilization-cliff) and DTI are both used in lending decisions — different metrics, complementary picture. [Good debt vs. bad debt](./good-debt-vs-bad-debt) covers how lenders think about debt quality.*
Frequently Asked Questions
what is a good debt to income ratio
A good debt-to-income ratio is typically below 36%, meaning your monthly debt payments don't exceed 36% of gross income. Most lenders use this threshold to approve mortgages, though some accept up to 43% for well-qualified borrowers. Exceeding these benchmarks significantly limits borrowing capacity.
how do I calculate my debt to income ratio
Divide your total monthly debt payments by your gross monthly income, then multiply by 100. Include mortgage, car loans, student loans, and minimum credit card payments. For example: $2,000 in payments ÷ $5,000 gross income = 0.40 or 40% DTI.
does debt to income ratio affect credit score
Debt-to-income ratio doesn't directly affect credit scores, which rely on payment history and credit utilization. However, it determines lending approval, and denied applications can impact your score indirectly. Lenders view DTI separately from credit scores during qualification.