Debt-to-Income Ratio Calculator
Compute your debt-to-income (DTI) ratio — total monthly debt payments divided by gross monthly income, expressed as a percentage. The single most important number lenders look at when deciding whether to approve a mortgage, auto loan, or any other significant credit.
Last updated: May 2026
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About this calculator
The debt-to-income ratio (DTI) measures how much of your gross (pre-tax) monthly income is consumed by required debt payments. The formula is DTI = (monthly debt payments ÷ gross monthly income) × 100. Monthly debt payments include the required minimums on every debt obligation: mortgage or rent (PITI for housing), auto loans, student loans, credit-card minimums, personal loans, child support, alimony, and any other contractually required payment. Gross monthly income is your before-tax income from all sources: salary, bonuses, self-employment, investment dividends, alimony received, child support received, and stable secondary income (typically averaged over 2 years if variable). Variables: monthlyDebt and monthlyIncome must both be > 0; monthlyIncome > 0 is required to avoid division by zero. There are two flavors of DTI: front-end DTI (housing-only — just PITI ÷ income) and back-end DTI (total — all debts ÷ income); this calculator computes back-end DTI, which is what most consumer lenders use. Lender benchmarks: most US mortgage lenders cap back-end DTI at 43% for qualified mortgages (CFPB rule), with sweet spots around 36% or lower; FHA loans allow up to 50% in special cases; conventional loans tighten to ~28% front-end and 36% back-end for the best rates. Above 50% DTI you may struggle to get any major credit, and above 60% you are considered financially distressed. Edge cases: income = 0 makes DTI undefined (and means you should not be borrowing); very high monthly debt that exceeds income produces DTI > 100% (mathematically valid but indicates severe trouble). DTI ignores assets and net worth, so a high-DTI borrower with substantial savings is treated the same as one without — which is why lenders also look at credit score, cash reserves, and down payment.
How to use
Example 1 — Solid borrower. Your gross monthly income is $6,000 (≈$72,000/year). Your monthly debt payments are $1,500 mortgage + $350 car loan + $150 credit card minimums = $2,000. Enter Monthly Debt = 2000, Monthly Income = 6000. DTI = (2000 / 6000) × 100 = 33.33%. ✓ A 33% DTI is comfortable: well under the 36% conventional-loan sweet spot and the 43% qualified-mortgage cap. You have meaningful capacity for additional debt if needed without crossing into lender-risk territory. Example 2 — Stretched borrower. Income $5,000/month, debts $1,800 mortgage + $400 car + $250 student loans + $200 credit cards = $2,650. Enter 2650, 5000. DTI = (2650 / 5000) × 100 = 53%. ✓ This exceeds the 43% conventional cap and approaches the 50% FHA ceiling — borrowing more would likely require a co-signer or a higher interest rate. Lenders may also flag this as a sign of financial fragility: a 10% income drop would push DTI past 58%, leaving little room for an emergency expense.
Frequently asked questions
What is the difference between front-end and back-end DTI?
Front-end DTI (also called housing DTI) is just your housing expense ÷ gross income — typically PITI (principal, interest, taxes, insurance) for a mortgage or your rent if you don't own. Lenders generally want front-end DTI below 28%. Back-end DTI (also called total DTI) adds all other monthly debt payments — auto loans, student loans, credit-card minimums, personal loans — to the housing payment. Most lenders use back-end DTI as the headline number; the standard upper limit is 43% for a qualified mortgage under CFPB rules, though FHA loans allow up to 50% with compensating factors and some lenders prefer 36% for the best rates. Always check which DTI your lender is asking about; the two can be very different for borrowers with substantial non-housing debt.
Which debts should I include in my DTI calculation?
Include every recurring contractual payment: mortgage or rent (with taxes and insurance), home equity loans, auto loans, student loans (use the actual minimum, not the income-driven amount if you're on an IDR plan — lenders typically use the standard amortising payment or 1% of balance), credit-card minimum payments, personal loans, lines of credit you actively use, alimony or child support you owe (received counts as income), and any other regularly scheduled debt payment. Do NOT include: utilities, phone bill, insurance premiums (other than home/auto), groceries, entertainment, or anything that isn't a debt repayment. Discretionary expenses are part of your cash-flow analysis but not your DTI. Some lenders also exclude student loans that are deferred and won't come due during the new loan's term; check before assuming.
What DTI do I need to qualify for a mortgage?
For a conventional mortgage with the best rates, lenders typically want back-end DTI ≤ 36%, with some flexibility up to 45%. The CFPB's "qualified mortgage" rule caps DTI at 43% for full safe-harbor status, though Fannie/Freddie loans can go up to 50% with strong compensating factors (excellent credit, large down payment, substantial cash reserves). FHA loans are more lenient — up to 50% back-end DTI is common, sometimes 55% with manual underwriting. VA loans don't have a strict DTI cap but residual-income requirements effectively cap most borrowers around 41–50%. Jumbo loans typically require 38–43% or lower. Beyond DTI, lenders also weigh credit score (700+ helps a lot), down payment (20%+ avoids PMI), and cash reserves (6+ months of payments helps). If your DTI is borderline, paying down a small high-payment debt before applying can swing approval.
What are the most common mistakes people make calculating DTI?
The first is using net (after-tax) income instead of gross — this inflates DTI by about 25–35% depending on your tax bracket, making you look much more stretched than lenders will see you. The second is forgetting to include all debts — missing a student loan or a credit-card minimum is common and produces a flattering but wrong number. The third is using the actual amount you pay on a debt rather than the required minimum; if you pay $500/month on a card whose minimum is $50, lenders only count the $50 (though paying more is better for your credit). The fourth is including discretionary expenses (utilities, subscriptions, groceries) — DTI is debt-specific, not a budget summary. The fifth is averaging variable income incorrectly; lenders typically require a 2-year average for bonuses and self-employment, and "estimated future income" rarely counts. Finally, people often forget that DTI is for current obligations, so the new loan payment must be included in the calculation when assessing affordability of a new debt.
When should I not use this calculator?
Skip it for non-debt financial-health questions; DTI tells you about debt burden but ignores assets, net worth, savings rate, and cash flow flexibility. Do not use it as the sole measure of affordability — a 30% DTI can be unsustainable if income is unstable or savings are zero, while a 45% DTI can be fine for someone with substantial cash reserves and reliable income. It is the wrong tool when income or debt is highly variable (commission-based jobs, freelance income, seasonal businesses); lenders use specific averaging rules that this simple ratio doesn't capture. Avoid it for business-loan analysis — corporate equivalents like Debt Service Coverage Ratio (DSCR) or Debt-to-EBITDA are more appropriate. Finally, do not use it across countries or financial systems without checking conventions; some markets use net-of-tax DTI, some include all housing costs (utilities, HOA), and lender thresholds vary by jurisdiction.