Mortgage Affordability Calculator
Estimate a home price from income, monthly debts, down payment, rate, term, housing costs, and user-selected housing and total DTI ratio assumptions. Ratios are illustrative and adjustable — not universal lender rules. This is not underwriting or approval.
Your results will appear here
Enter your assumptions and calculate to see the estimated result and supporting details.
How this calculator works
Enter gross annual income, monthly debt obligations, down payment, interest rate, term, property tax, insurance, HOA, PMI, and maximum housing / total DTI ratios.
The calculator takes the binding housing payment, subtracts ancillary costs for a P&I allowance, then reverses the mortgage formula for loan amount and home price.
Formula / methodology
Housing ceiling = Monthly income × housing ratio DTI housing = Monthly income × total DTI − debts Housing payment = min(ceiling, DTI housing) P&I = Housing payment − tax/12 − insurance/12 − HOA − PMI Loan = reverse installment(P&I) Home price = Loan + Down payment
- Default 28% / 36% ratios are illustrative assumptions you can change. Lenders use varying criteria.
- If total DTI leaves no room for housing, or ancillary costs consume the housing payment, the calculator reports a clear limitation.
- Cross-check: feeding the result into the Mortgage calculator should reproduce approximately the same estimated housing payment.
Worked example
With $120,000 income, $500 monthly debts, 28% housing / 36% DTI, the binding housing payment is $2,800.
After $500 tax, $150 insurance, and $100 HOA monthly, P&I allowance is $2,050. At 6.5% for 30 years plus $50,000 down, estimated home price is about $374,332.18.
Important assumptions
- Not underwriting or lender approval.
- Housing and DTI ratios are user assumptions, not mandates.
- Debt obligations are whatever you enter — not automatically scraped from credit reports.
- Property tax, insurance, HOA, and PMI are user estimates.
Common questions
Yes. They are defaults for illustration only. Enter the assumptions you want to explore; lenders may use different thresholds.
The lower total-DTI constraint can bind naturally. That is mathematically valid and not rejected.
No. It reports an estimated home price under the selected income, debt, ratio, and financing assumptions.
Rounding of cents on reverse vs forward installment math can create small differences; they should stay within cents-level tolerance for the housing payment.