Maximum DTI Loan Calculator

Find the largest loan your income can support. Adjust debts, rates, and term for accuracy. Download results, share numbers, and plan confidently every month.

Enter your details

Numbers can include commas. Use your lender’s DTI target and realistic housing costs.

Before taxes and deductions.
Loans, cards, support, student debt.
Common targets: 36, 43, or 50.
Housing-only ratio, often near 28–31.
Use your best quoted rate.
Longer terms may increase borrowing, not always affordability.
If unknown, use a cautious estimate.
Often applies with low down payment.
Maintenance set-aside, utilities, or fees.
Example: 20 for percent, or 15000 as amount.
Reset

Tip: Use existing debts from a credit report to reduce surprises.

Example data table

These examples show how DTI limits and monthly costs can change borrowing capacity.

Monthly income Max DTI Existing debts Monthly costs* Rate Term Estimated max loan Est. max home price (20% down)
$6,500 43% $650 $450 6.25% 30y $222,505 $278,131
$8,000 45% $1,200 $600 5.75% 20y $256,380 $320,475
$5,000 36% $400 $350 7.00% 15y $116,819 $146,023
*Monthly costs are taxes, insurance, HOA, PMI, and other fees combined.

Formula used

This calculator estimates the largest loan that fits your DTI limit.
  1. Debt-to-income ratio
    DTI = Total Monthly Debt ÷ Gross Monthly Income
  2. Maximum total debt allowed
    MaxDebt = Income × (MaxDTI% ÷ 100)
  3. Housing payment budget
    HousingBudget = MaxDebt − ExistingDebts
    If you enable the front-end cap, we use the smaller of back-end and front-end housing limits.
  4. Max principal & interest
    MaxP&I = HousingBudget − (Taxes + Insurance + HOA + PMI + Other)
  5. Loan amount from payment
    With monthly rate r and total payments n:
    Payment = P × r ÷ (1 − (1 + r)−n)
    Rearranged to solve for principal P:
    P = Payment × (1 − (1 + r)−n) ÷ r
    If r = 0, then P = Payment × n.

How to use this calculator

  1. Enter your gross monthly income and existing debt payments.
  2. Set your maximum DTI limit based on a target guideline.
  3. Add realistic monthly housing costs like taxes and insurance.
  4. Choose an interest rate and loan term for your estimate.
  5. Optionally apply the front-end cap for a stricter result.
  6. Click Calculate maximum loan to view results above.
  7. Download your results as CSV or PDF for sharing.
Practical tip: If your costs are uncertain, raise them slightly to stress-test affordability.

Debt-to-income thresholds used in underwriting

DTI measures monthly debt as a share of gross income. Many programs target 36% to 43% back-end DTI, while some allow higher. If income is 6,500 and the limit is 43%, the total debt budget is 2,795. After 650 in existing debts, the housing budget becomes 2,145 before taxes, insurance, and fees.

Why housing add-ons change the maximum loan

Borrowing capacity depends on the principal-and-interest payment you can support after escrows. Property taxes, insurance, HOA dues, PMI, and other fees behave like fixed monthly debt. A 450 monthly add-on reduces available P&I by 450, which can cut the estimated loan amount by tens of thousands. Accurate escrows usually matter more than small DTI tweaks.

Interest rate sensitivity is usually the biggest lever

Amortization makes affordability rate-sensitive. On a 30-year term, a 1% rate increase often reduces a payment-based loan estimate by roughly 8% to 12%, depending on the starting rate. The sensitivity table and chart help you compare outcomes at your DTI limit across nearby rates, so you can see how much risk a rate move creates.

Loan term trade-offs: higher approvals versus higher interest

Longer terms lower the payment and can increase the payment-based principal you can carry. Moving from 20 years to 30 years can raise the estimated maximum loan, but total interest paid generally rises. If qualification is the priority, longer terms may help; if lifetime cost is the priority, shorter terms may be better.

Using front-end caps and buffers for safer planning

Some lenders apply a front-end housing ratio, often near 28% to 31%, to limit housing costs even when back-end DTI permits more. Enabling the front-end cap makes the estimate more conservative. For planning, leave a 5% buffer under your target DTI and include a small reserve for maintenance. Aim for a payment that remains comfortable through changing expenses.

FAQs

1. What debts should I include in existing monthly debts?

Include required monthly payments for credit cards, auto loans, student loans, personal loans, and support obligations. Exclude utilities and groceries unless they are billed as fixed debts. Use the amount that appears on your statement or credit report.

2. Should I use gross or net income?

Use gross monthly income because DTI guidelines are typically based on pre‑tax income. If your pay varies, use an average of recent months. For self‑employed borrowers, use a conservative income figure consistent with documented earnings.

3. Why does a front-end cap change my result?

A front-end cap limits housing costs as a percentage of income, often around 28% to 31%. If your back-end DTI allows more, the cap can still reduce the housing budget, lowering the maximum principal-and-interest payment and the estimated loan amount.

4. How accurate is the maximum home price estimate?

It is a planning estimate that combines the calculated loan amount with your down payment assumption. Actual pricing depends on appraisal, program limits, closing costs, and local taxes or insurance. Use it to set a range, then confirm with lender quotes.

5. What happens if my max principal and interest is negative?

A negative value means existing debts and housing add-ons exceed your allowed budget at the selected DTI limit. Reduce monthly costs, pay down debts, increase income, or choose a different DTI target. Recheck using realistic escrows and fees.

6. Can I download results without recalculating?

CSV export uses your most recent calculation stored in the browser session, so it works after you calculate once. The PDF button is enabled only when results are visible. If you clear cookies or refresh sessions, run the calculation again.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.