Debt-to-Income Ratio Calculator
The first number a mortgage lender computes about you. Enter your gross income and monthly debts to see both ratios and where they sit against common underwriting guidelines.
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What a debt-to-income ratio is
DTI is the share of your gross monthly income already spoken for by debt. Lenders compute two versions. The front-end ratio counts housing alone. The back-end ratio — the one that usually decides things — adds every other monthly debt obligation: car loans, student loans, credit card minimums, personal loans, and support payments.
What does not count surprises people: utilities, groceries, insurance premiums, phone plans, childcare, and subscriptions are living expenses, not debts, and lenders exclude them all. That is also the ratio's blind spot — a DTI a lender likes can still belong to a stretched budget.
The guideline numbers
The traditional conventional-lending guideline is 28/36: housing at or below 28% of gross income, total debt at or below 36%. Above that, many programs still lend — some up to a back-end ratio around 43%, a figure with roots in the qualified-mortgage rules — but terms tighten and compensating factors matter more. These are conventions, not laws, and every lender applies its own overlays.
A worked example
Gross income of $6,000 a month, rent of $1,800, a $350 car payment, $150 of student loans, and $100 of credit card minimums. Front-end: 1,800 ÷ 6,000 = 30%. Back-end: 2,400 ÷ 6,000 = 40%.
That 40% sits between the 36% guideline and the 43% ceiling — mortgage-qualifiable with many lenders, but with little headroom. Paying the car loan off would drop the back end to 34.2% and move the file from "tight" to comfortable, which is exactly the kind of decision this ratio is built to inform.
Lowering the ratio
- Retire a payment, not just a balance. DTI counts monthly payments. Eliminating a $350 car payment helps immediately; paying a loan half down often does not change its payment at all.
- Mind the minimums. Card minimums scale with balances, so paying revolving debt down does reduce the counted figure.
- Document more income. The denominator matters as much as the numerator, but lenders only count income that is regular and provable.
- Avoid new obligations before applying. A financed phone or a new car lease lands directly on the back end at the worst time.
What this does not tell you
DTI uses gross income, but you live on net income. At a 40% back-end ratio, debt can easily consume more than half of take-home pay once taxes are gone. Check the result against the take-home pay calculator to see the ratio in after-tax terms — the version your monthly budget actually feels.
See our methodology for how these tools are built and tested.
Frequently asked questions
Do utilities, insurance, or groceries count in DTI?
No. Only debt obligations count: housing, loan payments, credit card minimums, and court-ordered support. Living expenses are excluded entirely — which is why a lender-acceptable DTI is not proof of an affordable life.
Which income counts — gross or take-home?
Gross, before taxes and deductions. Lenders also want it regular and documentable: salary, steady hourly wages, and established self-employment income count; irregular windfalls generally do not.
What DTI do I need for a mortgage?
Conventional guidance prefers a back-end ratio at or below 36%, and many programs lend up to around 43% with compensating factors; some go further. There is no single national cutoff — each lender and program sets its own limits.
Lower is stronger everywhere: it widens loan choices and can improve pricing.
Do credit card balances count, or just the payments?
Only the minimum payments enter the ratio. The balances affect DTI indirectly — larger balances mean larger minimums — and affect your credit utilisation separately. If you pay in full each month, the lender still counts the statement minimum.
Is a student loan in deferment counted?
Usually yes. Most mortgage programs impute a payment even when nothing is currently due — commonly a small percentage of the balance or the future amortizing payment. Rules differ by program, so a deferred loan rarely disappears from the calculation.
Related calculators
This calculator is provided for general educational and estimation purposes only. It does not constitute financial or lending advice, and it is not a qualification decision. The 28%, 36%, and 43% figures are conventional guidelines; individual lenders and loan programs set their own limits and weigh many factors beyond DTI.