Loan Affordability Calculator
Lenders determine how much you can borrow based on your debt-to-income ratio (DTI) — total monthly debt payments divided by gross monthly income. This calculator shows your maximum loan amount at three DTI levels so you know what to realistically expect.
Enter your gross monthly income, existing monthly debt payments, and desired loan terms to see how much you can borrow at conservative, moderate, and aggressive DTI thresholds.
| DTI Threshold | Max New Payment | Max Loan Amount | Total Interest |
|---|
How Lenders Calculate How Much You Can Borrow
Every lender — personal loan, auto, mortgage — uses debt-to-income ratio (DTI) as a primary affordability metric. DTI = (all monthly debt payments) ÷ (gross monthly income). If you earn $7,000/month gross and have $1,400 in monthly debt payments, your DTI is 20%. Lenders set a maximum DTI threshold; your new loan's monthly payment plus existing debts cannot exceed it.
The most common DTI thresholds: 28% front-end (housing costs only — used for mortgages), 36% back-end (all debts — preferred by most lenders), and 43% maximum (absolute ceiling for qualified mortgages; many personal lenders use this too). The room between your current DTI and the threshold determines how much more debt you can take on.
Why DTI Matters More Than Credit Score for Large Loans
Credit score measures your payment reliability history. DTI measures whether your cash flow can support the new payment going forward. A borrower with a 780 FICO score and 45% DTI may be denied, while a borrower with a 680 FICO score and 22% DTI is approved. Lenders know that high credit scores don't prevent defaults if borrowers are stretched too thin on cash flow. Both matter — but DTI is increasingly the binding constraint for borrowers with otherwise good credit.
| DTI Range | Rating | Lender View |
|---|---|---|
| Under 28% | Excellent | Best rates, highest approval odds |
| 28%–36% | Good | Preferred range, standard rates |
| 36%–43% | Acceptable | May still qualify, higher rates possible |
| Above 43% | High risk | Likely denied by conventional lenders |
How to Improve Your DTI Before Applying
Two levers: reduce existing debt payments or increase income. Paying off a car loan, credit card, or small personal loan before applying removes that payment from your DTI and directly increases how much new debt you can take on. If you have a $300/month car payment and you pay it off, your available debt capacity increases by $300/month — which at 10% for 3 years translates to roughly $9,000 in additional loan capacity.
To see how much debt you can comfortably manage alongside other financial goals, build your complete picture with the Monthly Budget Calculator. For specific debt payoff strategies, use the Debt Payoff Calculator.
Frequently Asked Questions
What is a debt-to-income (DTI) ratio?
DTI = total monthly debt payments ÷ gross monthly income. If you earn $7,000/month and pay $1,400 in monthly debt obligations, your DTI is 20%. Lenders use DTI to determine how much additional debt your cash flow can support. Most prefer below 36%; 43% is the common maximum for conventional loans.
What DTI ratio is good?
Under 28% is excellent; 28%–36% is good and gets the best loan terms; 36%–43% is acceptable but may result in higher rates; above 43% is high risk and often results in denial from conventional lenders. Aim for below 36% before applying for significant new debt.
What debts count in the DTI calculation?
Monthly payments on: mortgage or rent, car loans, student loans (minimum payments), credit card minimums, personal loan payments, and child support/alimony. Utilities, insurance, phone, and subscriptions are generally not counted. The new loan's projected monthly payment is added to existing debts to calculate your post-loan DTI.
How can I qualify for a larger loan?
Pay off existing debts before applying (removes that payment from DTI), add a co-borrower with income, increase your income, or choose a longer loan term (reduces the monthly payment's DTI impact, though it increases total interest). The cleanest approach: reduce existing debts first to create more DTI room for the new loan.
Is DTI different from credit score?
Yes. DTI measures cash flow capacity (can you afford the monthly payment going forward?). Credit score measures payment history and creditworthiness. Both matter to lenders. A high credit score doesn't prevent denial if DTI is too high; a modest credit score can still qualify if DTI is low. Improving both by paying down debt simultaneously strengthens both metrics.
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