.hac-row { display: flex; flex-wrap: wrap; margin-bottom: 15px; }
.hac-col { flex: 1; min-width: 250px; padding: 10px; }
.hac-label { display: block; margin-bottom: 5px; font-weight: bold; color: #333; }
.hac-input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; }
.hac-btn { width: 100%; padding: 15px; background-color: #2c3e50; color: white; border: none; border-radius: 4px; font-size: 16px; cursor: pointer; transition: background 0.3s; font-weight: bold; }
.hac-btn:hover { background-color: #34495e; }
.hac-result-box { margin-top: 25px; padding: 20px; background-color: #fff; border-left: 5px solid #27ae60; box-shadow: 0 2px 5px rgba(0,0,0,0.1); display: none; }
.hac-result-title { font-size: 18px; color: #555; margin-bottom: 10px; }
.hac-result-value { font-size: 32px; color: #27ae60; font-weight: bold; margin-bottom: 10px; }
.hac-breakdown { font-size: 14px; color: #666; line-height: 1.6; }
.hac-article { margin-top: 40px; padding-top: 20px; border-top: 1px solid #ddd; }
.hac-article h2 { color: #2c3e50; }
.hac-article p { line-height: 1.6; color: #444; margin-bottom: 15px; }
.hac-article ul { margin-bottom: 15px; padding-left: 20px; }
.hac-article li { margin-bottom: 5px; color: #444; }
function calculateAffordability() {
// Get inputs
var annualIncome = parseFloat(document.getElementById('hacAnnualIncome').value);
var monthlyDebts = parseFloat(document.getElementById('hacMonthlyDebts').value);
var downPayment = parseFloat(document.getElementById('hacDownPayment').value);
var interestRate = parseFloat(document.getElementById('hacInterestRate').value);
var loanTermYears = parseFloat(document.getElementById('hacLoanTerm').value);
var propertyTaxRate = parseFloat(document.getElementById('hacPropertyTax').value);
var insuranceYearly = parseFloat(document.getElementById('hacInsurance').value);
var dtiRatio = parseFloat(document.getElementById('hacDTIRatio').value);
// Validation
if (isNaN(annualIncome) || isNaN(interestRate) || isNaN(loanTermYears)) {
alert("Please enter valid numbers for Income, Interest Rate, and Loan Term.");
return;
}
// Defaults for empty optional fields
if (isNaN(monthlyDebts)) monthlyDebts = 0;
if (isNaN(downPayment)) downPayment = 0;
if (isNaN(propertyTaxRate)) propertyTaxRate = 0;
if (isNaN(insuranceYearly)) insuranceYearly = 0;
if (isNaN(dtiRatio)) dtiRatio = 36;
// 1. Calculate Monthly Gross Income
var monthlyIncome = annualIncome / 12;
// 2. Calculate Max Allowable Monthly Payment (PITI) based on DTI
// Formula: (Monthly Income * DTI%) – Existing Monthly Debts
var maxTotalMonthlyPayment = (monthlyIncome * (dtiRatio / 100)) – monthlyDebts;
// If existing debts are too high, affordability is zero
if (maxTotalMonthlyPayment <= 0) {
displayResults(0, 0, 0, 0, 0);
return;
}
// 3. Solve for Home Price (H)
// Total Payment = PrincipalAndInterest(LoanAmount) + Tax(H) + Insurance
// LoanAmount = H – DownPayment
// Tax = (H * TaxRate) / 12
// Insurance = InsuranceYearly / 12
// PI Formula Factor: (r(1+r)^n) / ((1+r)^n – 1)
var r = (interestRate / 100) / 12;
var n = loanTermYears * 12;
var mortgageFactor = 0;
if (r === 0) {
mortgageFactor = 1 / n;
} else {
mortgageFactor = (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) – 1);
}
var monthlyTaxRate = (propertyTaxRate / 100) / 12;
var monthlyInsurance = insuranceYearly / 12;
// Equation: MaxPayment = [(H – DownPayment) * mortgageFactor] + [H * monthlyTaxRate] + monthlyInsurance
// MaxPayment – monthlyInsurance + (DownPayment * mortgageFactor) = H * (mortgageFactor + monthlyTaxRate)
// H = (MaxPayment – monthlyInsurance + (DownPayment * mortgageFactor)) / (mortgageFactor + monthlyTaxRate)
var numerator = maxTotalMonthlyPayment – monthlyInsurance + (downPayment * mortgageFactor);
var denominator = mortgageFactor + monthlyTaxRate;
var homePrice = numerator / denominator;
// Edge case: If home price is less than down payment (math artifact), cap it or handle logic
if (homePrice = D.
// However, with this formula, if H < D, it implies no loan needed.
var loanAmount = homePrice – downPayment;
if (loanAmount < 0) loanAmount = 0;
// Calculate Components for Display
var calculatedTax = homePrice * monthlyTaxRate;
var calculatedPI = loanAmount * mortgageFactor;
// If loan is 0, PI is 0
if (loanAmount <= 0) calculatedPI = 0;
var totalMonthly = calculatedPI + calculatedTax + monthlyInsurance;
displayResults(homePrice, calculatedPI, calculatedTax, monthlyInsurance, totalMonthly);
}
function displayResults(price, pi, tax, ins, total) {
var formatCurrency = function(num) {
return "$" + num.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0});
};
document.getElementById('hacMaxPrice').innerText = formatCurrency(price);
document.getElementById('hacPI').innerText = formatCurrency(pi);
document.getElementById('hacTax').innerText = formatCurrency(tax);
document.getElementById('hacIns').innerText = formatCurrency(ins);
document.getElementById('hacTotalMonthly').innerText = formatCurrency(total);
document.getElementById('hacResult').style.display = 'block';
}
Home Affordability Calculator
30 Years
20 Years
15 Years
10 Years
Maximum Home Price You Can Afford:
$0
Monthly Payment Breakdown:
Principal & Interest: $0
Property Taxes: $0
Home Insurance: $0
Total Monthly Payment: $0
Principal & Interest: $0
Property Taxes: $0
Home Insurance: $0
Total Monthly Payment: $0
How Much House Can I Really Afford?
Determining your home buying budget is the most critical step before browsing listings. This Home Affordability Calculator uses the "Debt-to-Income" (DTI) rule used by lenders to determine maximum loan amounts. It takes into account not just your mortgage payments, but also property taxes, insurance, and your existing debts.
Understanding the Key Factors
When calculating affordability, several variables impact your purchasing power:
- Debt-to-Income Ratio (DTI): Lenders typically prefer that your total monthly debt payments (mortgage + car loans + credit cards) do not exceed 36% to 43% of your gross monthly income.
- Interest Rate: Even a small increase in interest rates can significantly reduce your buying power by increasing your monthly mortgage payment.
- Property Taxes & Insurance: These "hidden" costs are part of your monthly escrow payment. High property tax areas will lower the maximum home price you can afford.
The 28/36 Rule
A common standard in real estate finance is the 28/36 rule. It suggests that your household expenses (mortgage, tax, insurance) should not exceed 28% of your gross monthly income, and your total debt (household expenses + other debts) should not exceed 36%. This calculator allows you to adjust the DTI limit to see how aggressive or conservative budgets affect your home price range.
Use this tool as a starting point. Always consult with a qualified mortgage lender to get a pre-approval letter for an exact figure.