{
  "slug": "house-affordability",
  "title": "House Affordability Calculator",
  "heading": "House Affordability Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/house-affordability",
  "summary": "How much house your income actually supports.",
  "description": "Lenders size a mortgage against your gross income and existing debt. The common guardrail is a 36% back-end debt-to-income ratio, meaning all monthly debt including the new mortgage stays under 36% of gross monthly income.",
  "formula": "Max payment = (Gross monthly income × DTI%) − existing debt. Loan is back-solved from that payment.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=house-affordability",
  "inputs": [
    {
      "id": "income",
      "label": "Gross annual income",
      "kind": "number",
      "hint": null,
      "default": 110000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "debts",
      "label": "Other monthly debt",
      "kind": "number",
      "hint": null,
      "default": 550,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "dti",
      "label": "Max DTI",
      "kind": "number",
      "hint": null,
      "default": 36,
      "unit": "%",
      "min": 10,
      "max": 55
    },
    {
      "id": "rate",
      "label": "Interest rate",
      "kind": "number",
      "hint": null,
      "default": 6.5,
      "unit": "%",
      "min": 0.1,
      "max": null
    },
    {
      "id": "years",
      "label": "Term",
      "kind": "number",
      "hint": null,
      "default": 30,
      "unit": "years",
      "min": 1,
      "max": null
    },
    {
      "id": "downPct",
      "label": "Down payment",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 100
    }
  ],
  "outputs": [
    {
      "id": "price",
      "label": "Affordable home price",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "loan",
      "label": "Supported loan amount",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "down",
      "label": "Down payment needed",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "budget",
      "label": "Max total housing payment",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "piBudget",
      "label": "Of that, principal + interest",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Gross annual income: 110000 $",
      "Other monthly debt: 550 $",
      "Max DTI: 36 %",
      "Interest rate: 6.5 %",
      "Term: 30 years",
      "Down payment: 10 %"
    ],
    "outputs": [
      "Affordable home price: $377,069.12",
      "Supported loan amount: $339,362.21",
      "Down payment needed: $37,706.91",
      "Max total housing payment: $2,750.00",
      "Of that, principal + interest: $2,145.00"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter gross annual income ($).",
      "Enter other monthly debt ($).",
      "Enter max dti (%).",
      "Enter interest rate (%).",
      "Enter term (years).",
      "Enter down payment (%).",
      "Read your affordable home price on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "income": 66000,
        "debts": 325,
        "dti": 22,
        "rate": 6.5,
        "years": 18,
        "downPct": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "income": 110000,
        "debts": 550,
        "dti": 36,
        "rate": 6.5,
        "years": 30,
        "downPct": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "income": 176000,
        "debts": 875,
        "dti": 55,
        "rate": 6.5,
        "years": 48,
        "downPct": 16
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "How does the house affordability calculator work?",
      "a": "Lenders size a mortgage against your gross income and existing debt. The common guardrail is a 36% back-end debt-to-income ratio, meaning all monthly debt including the new mortgage stays under 36% of gross monthly income. The underlying maths is: Max payment = (Gross monthly income × DTI%) − existing debt. Loan is back-solved from that payment."
    },
    {
      "q": "What do I need to enter?",
      "a": "6 values: gross annual income, other monthly debt, max dti, interest rate, term, and down payment. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the affordable home price result mean?",
      "a": "It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/mortgage",
    "https://www.revenuelab.fyi/toolbox/down-payment"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — House Affordability Calculator (https://www.revenuelab.fyi/toolbox/house-affordability)"
}