Mortgage Affordability Calculator
This calculator helps you estimate how much you can afford to borrow for a mortgage based on your income, debts, and desired down payment. It's a crucial tool to understand your borrowing capacity before house hunting.
Calculate Affordability
function calculateAffordability() {
var annualIncome = parseFloat(document.getElementById("annualIncome").value);
var monthlyDebt = parseFloat(document.getElementById("monthlyDebt").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTerm = parseFloat(document.getElementById("loanTerm").value);
var maxDTI = parseFloat(document.getElementById("maxDTI").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(annualIncome) || annualIncome <= 0 ||
isNaN(monthlyDebt) || monthlyDebt < 0 ||
isNaN(downPayment) || downPayment < 0 ||
isNaN(interestRate) || interestRate <= 0 ||
isNaN(loanTerm) || loanTerm <= 0 ||
isNaN(maxDTI) || maxDTI <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
var monthlyIncome = annualIncome / 12;
var maxAllowableMonthlyDebt = monthlyIncome * (maxDTI / 100);
var maxAllowableMortgagePayment = maxAllowableMonthlyDebt – monthlyDebt;
if (maxAllowableMortgagePayment 0) {
principalLimit = maxAllowableMortgagePayment * (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1) / (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments));
} else {
// Handle the case of 0% interest rate, though unrealistic for mortgages
principalLimit = maxAllowableMortgagePayment * numberOfPayments;
}
var maxAffordableHomePrice = principalLimit + downPayment;
resultDiv.innerHTML =
"
Estimated Maximum Mortgage Amount: $" + principalLimit.toFixed(2) + "" +
"
Estimated Maximum Affordable Home Price: $" + maxAffordableHomePrice.toFixed(2) + "";
}
.calculator-container {
font-family: sans-serif;
border: 1px solid #ddd;
padding: 20px;
border-radius: 8px;
max-width: 600px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
color: #333;
margin-bottom: 15px;
}
.calculator-container p {
color: #555;
line-height: 1.6;
margin-bottom: 20px;
}
.inputs {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
gap: 15px;
margin-bottom: 20px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #444;
}
.form-group input[type="number"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
.form-group input[type="number"]:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 0 2px rgba(0,123,255,.25);
}
.calculator-container button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 5px;
font-size: 18px;
cursor: pointer;
transition: background-color 0.3s ease;
margin-top: 10px;
}
.calculator-container button:hover {
background-color: #0056b3;
}
#result {
margin-top: 25px;
padding: 15px;
border: 1px dashed #ccc;
border-radius: 5px;
background-color: #e9ecef;
text-align: center;
}
#result p {
margin: 5px 0;
font-size: 1.1em;
}