Understanding how much house you can afford is a crucial first step in the home-buying process. This calculator helps you estimate your potential mortgage payment based on several key factors. Remember, this is an estimate, and your actual mortgage approval will depend on a lender's detailed assessment of your financial situation.
#mortgage-calculator {
font-family: sans-serif;
max-width: 500px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ddd;
border-radius: 8px;
background-color: #f9f9f9;
}
.form-group {
margin-bottom: 15px;
}
.form-group label {
display: block;
margin-bottom: 5px;
font-weight: bold;
}
.form-group input[type="number"] {
width: calc(100% – 12px);
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
}
button {
background-color: #4CAF50;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
}
button:hover {
background-color: #45a049;
}
#result {
margin-top: 20px;
padding: 15px;
border: 1px solid #eee;
border-radius: 4px;
background-color: #fff;
text-align: center;
font-size: 1.1em;
}
#result p {
margin: 0 0 10px 0;
}
#result strong {
color: #333;
}
function calculateMortgageAffordability() {
var annualIncome = parseFloat(document.getElementById("annualIncome").value);
var monthlyDebt = parseFloat(document.getElementById("monthlyDebt").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var loanTerm = parseInt(document.getElementById("loanTerm").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Basic validation
if (isNaN(annualIncome) || isNaN(monthlyDebt) || isNaN(downPayment) || isNaN(loanTerm) || isNaN(interestRate)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
// Rule of thumb: Debt-to-Income (DTI) ratio for housing should not exceed 28%
// and total DTI (including housing) should not exceed 36%.
// We'll calculate the maximum affordable monthly payment based on these.
var maxHousingPayment = annualIncome * 0.28 / 12;
var maxTotalDebtPayment = annualIncome * 0.36 / 12;
var maxMortgagePaymentAllowed = maxTotalDebtPayment – monthlyDebt;
// We use the lower of the two calculated maximums to be conservative
var affordableMonthlyMortgage = Math.min(maxHousingPayment, maxMortgagePaymentAllowed);
if (affordableMonthlyMortgage 0 && numberOfPayments > 0) {
var numerator = monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments);
var denominator = Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1;
var principalMultiplier = numerator / denominator;
maxLoanAmount = affordableMonthlyMortgage / principalMultiplier;
} else if (monthlyInterestRate === 0 && numberOfPayments > 0) {
// Handle zero interest rate case
maxLoanAmount = affordableMonthlyMortgage * numberOfPayments;
}
var estimatedMaxHomePrice = maxLoanAmount + downPayment;
resultDiv.innerHTML = "Estimated Maximum Affordable Monthly Mortgage Payment (Principal & Interest): $" + affordableMonthlyMortgage.toFixed(2) + "" +
"Estimated Maximum Loan Amount: $" + maxLoanAmount.toFixed(2) + "" +
"Estimated Maximum Affordable Home Price (including down payment): $" + estimatedMaxHomePrice.toFixed(2) + "";
}