Mortgage Affordability Calculator
Use this calculator to estimate the maximum mortgage amount you can afford. This calculation is a guideline and does not constitute financial advice. Consult with a mortgage professional for personalized guidance.
Calculate Affordability
Your Estimated Mortgage Affordability:
Maximum Monthly Mortgage Payment You Can Afford: —
Estimated Maximum Mortgage Loan Amount: —
Estimated Maximum Home Price You Can Afford: —
function calculateMortgageAffordability() {
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) / 100;
var loanTerm = parseInt(document.getElementById("loanTerm").value);
var maxDTI = parseFloat(document.getElementById("maxDTI").value) / 100;
var resultsDiv = document.getElementById("results");
var maxMonthlyPaymentDisplay = document.getElementById("maxMonthlyPayment");
var maxLoanAmountDisplay = document.getElementById("maxLoanAmount");
var maxHomePriceDisplay = document.getElementById("maxHomePrice");
// Clear previous results
maxMonthlyPaymentDisplay.textContent = "–";
maxLoanAmountDisplay.textContent = "–";
maxHomePriceDisplay.textContent = "–";
if (isNaN(annualIncome) || isNaN(monthlyDebt) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(maxDTI) ||
annualIncome < 0 || monthlyDebt < 0 || downPayment < 0 || interestRate < 0 || loanTerm <= 0 || maxDTI <= 0) {
resultsDiv.innerHTML += "Please enter valid positive numbers for all fields.";
return;
}
var monthlyIncome = annualIncome / 12;
var maxTotalMonthlyDebt = monthlyIncome * maxDTI;
var maxMortgagePayment = maxTotalMonthlyDebt – monthlyDebt;
if (maxMortgagePayment 0) {
var numberOfPayments = loanTerm * 12;
var monthlyInterestRate = interestRate / 12;
// Formula for present value of an annuity (loan amount)
// PV = PMT * [1 – (1 + r)^-n] / r
maxLoanAmount = maxMortgagePayment * (1 – Math.pow(1 + monthlyInterestRate, -numberOfPayments)) / monthlyInterestRate;
} else { // Handle 0% interest rate scenario
maxLoanAmount = maxMortgagePayment * (loanTerm * 12);
}
var maxHomePrice = maxLoanAmount + downPayment;
maxMonthlyPaymentDisplay.textContent = "$" + maxMortgagePayment.toFixed(2);
maxLoanAmountDisplay.textContent = "$" + maxLoanAmount.toFixed(2);
maxHomePriceDisplay.textContent = "$" + maxHomePrice.toFixed(2);
}
.calculator-container {
font-family: sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 8px;
max-width: 600px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
margin-bottom: 20px;
color: #333;
}
.calculator-container p {
font-size: 0.9em;
color: #555;
margin-bottom: 20px;
line-height: 1.5;
}
.calculator-inputs {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
gap: 15px;
margin-bottom: 20px;
}
.input-group {
display: flex;
flex-direction: column;
}
.input-group label {
font-weight: bold;
margin-bottom: 5px;
color: #444;
}
.input-group input[type="number"] {
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 1em;
}
button {
background-color: #007bff;
color: white;
padding: 12px 20px;
border: none;
border-radius: 4px;
font-size: 1.1em;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #0056b3;
}
.calculator-results {
margin-top: 25px;
padding-top: 15px;
border-top: 1px solid #eee;
text-align: center;
}
.calculator-results h3 {
margin-bottom: 15px;
color: #333;
}
.calculator-results p {
font-size: 1.1em;
margin: 8px 0;
color: #444;
}
.calculator-results strong {
color: #007bff;
}