Affordability Range
Maximum home price
$640,040.42
Comfortable home price
$560,356.56
Max monthly housing budget
$4,316.67
Comfortable monthly budget
$3,733.33
Housing
Mortgage Affordability Calculator
Calculate maximum and comfortable home-price ranges with DTI constraints, taxes, insurance, HOA, and down payment assumptions.
Home Price Envelope
Comfort range vs hard maximum
Comfort home price
$560,356.56
Maximum home price
$640,040.42
Down payment
$90,000.00
Loan Principal View
Borrowing amount under each affordability threshold
Comfort loan principal
$470,356.56
Maximum loan principal
$550,040.42
How to use it
- Enter gross monthly income, recurring monthly debt payments, available down payment, rate, term, property tax, insurance, and HOA using lender-style numbers. If income is variable, use the lower end of what you can reliably document.
- Read maximum home price and monthly housing budget, then separate the comfortable payment from the absolute maximum. Common lender guideposts are housing <= 28% of gross income and total debt <= 36%, with many approvals stretching toward 43% back-end DTI.
- If the maximum affordability result is still well below actual homes in your target area, that is a market-access problem, not a budgeting tweak. If the payment only works at the lender maximum, the house may be financeable without being comfortable.
- Stress-test the result with a rate 1% higher and with a smaller down payment. If that version breaks your cash flow, lower the target price and run the mortgage payment amortization calculator before making offers.
- Re-run when income changes, a debt is paid off, or rates move by about 0.5% or more. Track front-end DTI, back-end DTI, and the all-in monthly housing cost you would actually carry.
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Always available for agents
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Tool contract JSON
https://aifinhub.io/contracts/mortgage-affordability-calculator.jsonStable input and output contract for this exact tool.
Human review
People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.
- /agent-tools.json - machine-readable tool index.
- /llms.txt - human-readable model discovery guide.
- /.well-known/webmcp.json - WebMCP capabilities manifest.
- /.well-known/ai-plugin.json - plugin-style discovery manifest.
{
"tool": "mortgage_affordability",
"annual_income": 140000,
"down_payment": 90000,
"monthly_debt_payments": 700,
"max_dti_percent": 43,
"mortgage_rate_percent": 6.5,
"loan_term_years": 30,
"property_tax_rate_percent": 1.2,
"annual_home_insurance": 2400,
"hoa_monthly": 0
} Expand developer notes
Agent playbook
- Resolve Mortgage Affordability Calculator from /agent-tools.json and open its contract before execution.
- Validate inputs against the contract schema instead of scraping labels from the page UI.
- Open the browser page only when a person wants to review charts, assumptions, or related tools.
Agent FAQ
Should ChatGPT, Claude, or another agent click through the UI?
No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.
When do tools show Quick and Advanced?
Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.
When should an agent still open the browser page?
Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.
Questions people usually ask
How much house can I afford?
The traditional 28/36 rule: mortgage payment (PITI — principal, interest, taxes, insurance) should not exceed 28% of gross monthly income, and total debt payments should not exceed 36%. At $80,000 annual income, maximum PITI is $1,867/month. With a 7% rate and 20% down, that supports a purchase price around $290,000-310,000 depending on taxes and insurance.
What is the real cost of a lower down payment?
Putting 10% down instead of 20% on a $400,000 home costs you: $40,000 less upfront, but adds PMI (~$120-180/month until you reach 20% equity), and increases the loan amount by $40,000 — adding ~$270/month at 7%. Total extra cost over 7 years (average time before refinancing): approximately $35,000-45,000.
Is it better to pay off the mortgage early or invest?
It depends on your mortgage rate. If your rate is below 4-5%, historical equity returns (7% real) favor investing over prepaying. If your rate is 6%+, paying down the mortgage offers a guaranteed 6% return — comparable to bonds. Most financial planners suggest maxing tax-advantaged accounts (401k, IRA) before extra mortgage payments regardless.
How much does a 1% difference in rate matter?
Significantly. On a $400,000 30-year mortgage: at 6.5% your payment is $2,528/month; at 7.5% it is $2,797/month — $269/month difference, or $96,840 over the loan life. At 8.5%, the payment reaches $3,073/month. Rate is the most important variable you can negotiate before closing.
Related Resources
Learn the decision before you act
Every link here is tied directly to Mortgage Affordability Calculator. Use the explanation, formula, examples, and benchmarks to pressure-test the calculator output from first principles.
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