Mortgage Payment Calculator
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
max-width: 1200px;
margin: 0 auto;
padding: 20px;
}
.calculator-container {
background: #fff;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr;
gap: 20px;
}
@media (min-width: 768px) {
.calc-grid {
grid-template-columns: 1fr 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 0.95em;
}
.input-group input, .input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #0073aa;
outline: none;
box-shadow: 0 0 0 2px rgba(0,115,170,0.2);
}
.calc-btn {
background-color: #0073aa;
color: white;
border: none;
padding: 12px 24px;
font-size: 16px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #005177;
}
.results-section {
background-color: #f9f9f9;
padding: 20px;
border-radius: 8px;
margin-top: 20px;
border-left: 5px solid #0073aa;
}
.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;
}
.result-label {
font-weight: 500;
color: #555;
}
.result-value {
font-weight: 700;
font-size: 1.1em;
color: #333;
}
.result-main {
font-size: 1.4em;
color: #0073aa;
}
.article-content {
margin-top: 40px;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
}
.article-content h3 {
color: #34495e;
margin-top: 25px;
}
.article-content p {
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-content li {
margin-bottom: 10px;
}
.error-msg {
color: #d32f2f;
font-size: 0.9em;
margin-top: 5px;
display: none;
}
Mortgage Calculator
Monthly Breakdown
Principal & Interest:
$0.00
Property Taxes:
$0.00
Home Insurance:
$0.00
HOA Fees:
$0.00
Total Monthly Payment:
$0.00
Loan Summary
Loan Amount:
$0.00
Total Interest Paid:
$0.00
Total Cost of Loan:
$0.00
function calculateMortgage() {
// Get input values
var homePrice = parseFloat(document.getElementById('mc-home-price').value);
var downPayment = parseFloat(document.getElementById('mc-down-payment').value);
var interestRate = parseFloat(document.getElementById('mc-interest-rate').value);
var loanTermYears = parseInt(document.getElementById('mc-loan-term').value);
var annualTax = parseFloat(document.getElementById('mc-property-tax').value);
var annualInsurance = parseFloat(document.getElementById('mc-insurance').value);
var monthlyHOA = parseFloat(document.getElementById('mc-hoa').value);
var errorMsg = document.getElementById('mc-error');
// Reset error
errorMsg.style.display = 'none';
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTermYears) ||
homePrice < 0 || downPayment < 0 || interestRate = home price
if (loanAmount 0) {
if (interestRate === 0) {
monthlyPrincipalInterest = loanAmount / numberOfPayments;
} else {
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var x = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPrincipalInterest = (loanAmount * x * monthlyInterestRate) / (x – 1);
}
}
// Calculate other monthly costs
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
// Handle NaNs for optional fields
if (isNaN(monthlyTax)) monthlyTax = 0;
if (isNaN(monthlyInsurance)) monthlyInsurance = 0;
if (isNaN(monthlyHOA)) monthlyHOA = 0;
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyInsurance + monthlyHOA;
// Totals
var totalCostOfLoan = (monthlyPrincipalInterest * numberOfPayments) + downPayment;
// Note: Total cost usually refers to Principal + Interest paid.
// Let's define it as Total Principal + Total Interest paid over term.
var totalPrincipalInterestPaid = monthlyPrincipalInterest * numberOfPayments;
var totalInterestPaid = totalPrincipalInterestPaid – loanAmount;
// Format Currency Function
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
// Update UI
document.getElementById('res-pi').innerHTML = fmt.format(monthlyPrincipalInterest);
document.getElementById('res-tax').innerHTML = fmt.format(monthlyTax);
document.getElementById('res-ins').innerHTML = fmt.format(monthlyInsurance);
document.getElementById('res-hoa').innerHTML = fmt.format(monthlyHOA);
document.getElementById('res-total-monthly').innerHTML = fmt.format(totalMonthlyPayment);
document.getElementById('res-loan-amount').innerHTML = fmt.format(loanAmount);
document.getElementById('res-total-interest').innerHTML = fmt.format(totalInterestPaid);
document.getElementById('res-total-cost').innerHTML = fmt.format(totalPrincipalInterestPaid);
}
// Initialize on load
window.onload = function() {
calculateMortgage();
};
Understanding Your Mortgage Estimate
Purchasing a home is likely the largest financial commitment you will make in your lifetime. Understanding how your monthly mortgage payment is calculated is essential for budgeting and determining exactly how much house you can afford. This Mortgage Calculator provides a comprehensive breakdown of the costs associated with homeownership.
How Mortgage Payments Are Calculated
A standard monthly mortgage payment consists of four main components, often referred to as PITI:
- Principal: The portion of your payment that goes toward paying down the original loan balance. In the early years of a loan, this amount is small, but it increases over time.
- Interest: The cost of borrowing money from the lender. This usually makes up the majority of your payment in the early years of a long-term loan.
- Taxes: Property taxes assessed by your local government. Lenders often collect this monthly and hold it in an escrow account to pay the tax bill when it's due.
- Insurance: Homeowners insurance protects your property against damage. Like taxes, this is often collected monthly in escrow.
The Impact of Interest Rates and Loan Terms
Even small changes in the Interest Rate can drastically affect your total monthly payment and the total cost of the loan. For example, on a $300,000 loan, a 1% difference in interest rate can save or cost you tens of thousands of dollars over the life of a 30-year term.
Similarly, the Loan Term plays a crucial role. A 15-year mortgage will have higher monthly payments than a 30-year mortgage because you are paying off the principal faster. However, the total interest paid over 15 years will be significantly lower than over 30 years.
Don't Forget Additional Costs
When calculating affordability, it is vital to include costs beyond the mortgage itself:
- HOA Fees: If you buy a condo or a home in a planned community, Homeowners Association fees are paid directly to the association, not the lender, but they still impact your monthly budget.
- Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's value, lenders often require PMI, which increases your monthly cost until you reach 20% equity.
How to Use This Calculator
Start by entering the Home Price and your planned Down Payment. Adjust the Interest Rate to match current market conditions. Don't forget to estimate your Property Taxes and Insurance—you can often find these estimates on real estate listing sites for similar properties in your area. Click "Calculate Payment" to see your estimated monthly obligation.