#mortgage-calculator-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.calc-header {
text-align: center;
margin-bottom: 30px;
border-bottom: 2px solid #f0f0f0;
padding-bottom: 20px;
}
.calc-header h2 {
margin: 0;
color: #2c3e50;
font-size: 28px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #555;
font-size: 14px;
}
.input-wrapper {
position: relative;
display: flex;
align-items: center;
}
.input-prefix, .input-suffix {
background: #f8f9fa;
padding: 10px 15px;
border: 1px solid #ddd;
color: #666;
font-weight: bold;
}
.input-prefix {
border-right: none;
border-radius: 4px 0 0 4px;
}
.input-suffix {
border-left: none;
border-radius: 0 4px 4px 0;
}
.calc-input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
font-size: 16px;
outline: none;
transition: border-color 0.3s;
}
.calc-input:focus {
border-color: #3498db;
}
.input-wrapper .calc-input {
border-radius: 0;
}
.input-wrapper .calc-input:first-child {
border-radius: 4px 0 0 4px;
}
.input-wrapper .calc-input:last-child {
border-radius: 0 4px 4px 0;
}
button.calc-btn {
background-color: #2980b9;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 20px;
transition: background-color 0.2s;
}
button.calc-btn:hover {
background-color: #1c6ea4;
}
#results-area {
margin-top: 30px;
background-color: #f8fbfd;
border: 1px solid #e1e8ed;
border-radius: 8px;
padding: 25px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
align-items: center;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
margin-top: 15px;
padding-top: 15px;
border-top: 2px solid #ddd;
}
.result-label {
color: #666;
font-size: 16px;
}
.result-value {
font-weight: bold;
color: #2c3e50;
font-size: 18px;
}
.result-total {
font-size: 24px;
color: #27ae60;
}
.seo-content {
margin-top: 50px;
line-height: 1.6;
color: #444;
}
.seo-content h3 {
color: #2c3e50;
margin-top: 25px;
margin-bottom: 15px;
}
.seo-content p {
margin-bottom: 15px;
}
.error-msg {
color: #e74c3c;
text-align: center;
margin-top: 10px;
display: none;
}
Understanding Your Mortgage Payment Components (PITI)
When preparing to buy a home, many buyers focus solely on the principal and interest payment. However, the true cost of homeownership is often represented by the acronym PITI: Principal, Interest, Taxes, and Insurance.
Principal & Interest: This is the core of your loan. The principal repays the amount you borrowed, while the interest is the cost of borrowing that money. In the early years of a 30-year mortgage, the majority of this portion goes toward interest.
Property Taxes: Local governments assess property taxes to fund public services like schools and roads. This amount can vary significantly by location and is usually paid into an escrow account monthly as part of your mortgage payment.
Homeowners Insurance: Lenders require you to carry insurance to protect the property against damage. Like taxes, the annual premium is typically divided by 12 and added to your monthly bill.
How Interest Rates Impact Affordability
Even a small fluctuation in interest rates can drastically change your monthly obligation. For example, on a $300,000 loan, a difference of just 1% in the interest rate can increase your monthly payment by hundreds of dollars over the life of the loan. Use the calculator above to scenario-test different rates to see what you can comfortably afford.
The Role of Down Payment
Your down payment reduces the principal loan amount directly. A larger down payment (typically 20% or more) not only lowers your monthly Principal & Interest payment but may also eliminate the need for Private Mortgage Insurance (PMI), further reducing your monthly costs.
function calculateMortgage() {
// Get inputs
var homePrice = parseFloat(document.getElementById('homePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanTerm = parseFloat(document.getElementById('loanTerm').value);
var propertyTax = parseFloat(document.getElementById('propertyTax').value);
var homeInsurance = parseFloat(document.getElementById('homeInsurance').value);
var hoaFees = parseFloat(document.getElementById('hoaFees').value);
// Error handling
var errorMsg = document.getElementById('error-message');
var resultsArea = document.getElementById('results-area');
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) ||
homePrice < 0 || downPayment < 0 || interestRate < 0 || loanTerm <= 0) {
errorMsg.style.display = 'block';
resultsArea.style.display = 'none';
return;
} else {
errorMsg.style.display = 'none';
}
// Handle optional fields empty inputs as 0
if (isNaN(propertyTax)) propertyTax = 0;
if (isNaN(homeInsurance)) homeInsurance = 0;
if (isNaN(hoaFees)) hoaFees = 0;
// Calculations
var principal = homePrice – downPayment;
// Prevent negative principal
if (principal < 0) principal = 0;
var monthlyRate = interestRate / 100 / 12;
var numberOfPayments = loanTerm * 12;
var monthlyPI = 0;
// Handle zero interest case
if (interestRate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
// Mortgage formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
monthlyPI = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
var monthlyTax = propertyTax / 12;
var monthlyIns = homeInsurance / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns + hoaFees;
// Display Results
resultsArea.style.display = 'block';
document.getElementById('result-pi').innerHTML = formatMoney(monthlyPI);
document.getElementById('result-tax').innerHTML = formatMoney(monthlyTax);
document.getElementById('result-ins').innerHTML = formatMoney(monthlyIns);
document.getElementById('result-hoa').innerHTML = formatMoney(hoaFees);
document.getElementById('result-total').innerHTML = formatMoney(totalMonthly);
}
function formatMoney(amount) {
return '$' + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}