.mc-row { display: flex; flex-wrap: wrap; gap: 20px; margin-bottom: 15px; }
.mc-col { flex: 1; min-width: 250px; }
.mc-label { display: block; font-weight: 600; margin-bottom: 5px; color: #333; }
.mc-input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; font-size: 16px; }
.mc-input:focus { border-color: #0073aa; outline: none; }
.mc-btn { background-color: #0073aa; color: white; padding: 12px 24px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; font-weight: bold; width: 100%; margin-top: 10px; transition: background 0.3s; }
.mc-btn:hover { background-color: #005177; }
.mc-result-box { background-color: #f7f9fc; border: 1px solid #d1d9e6; border-radius: 6px; padding: 20px; margin-top: 25px; display: none; }
.mc-result-row { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid #eee; }
.mc-result-row:last-child { border-bottom: none; }
.mc-total { font-size: 24px; color: #2c3e50; font-weight: 800; text-align: center; margin-bottom: 20px; }
.mc-error { color: #d63638; display: none; margin-top: 10px; font-weight: bold; }
.mc-article { margin-top: 40px; line-height: 1.6; color: #444; }
.mc-article h2 { color: #23282d; margin-top: 30px; }
.mc-article ul { margin-bottom: 20px; }
function calculateMortgage() {
// Get inputs
var homePrice = parseFloat(document.getElementById('mc-price').value);
var downPayment = parseFloat(document.getElementById('mc-down').value);
var interestRate = parseFloat(document.getElementById('mc-rate').value);
var loanTermYears = parseInt(document.getElementById('mc-term').value);
var annualTax = parseFloat(document.getElementById('mc-tax').value);
var annualIns = parseFloat(document.getElementById('mc-ins').value);
var monthlyHOA = parseFloat(document.getElementById('mc-hoa').value);
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) ||
isNaN(loanTermYears) || homePrice <= 0) {
document.getElementById('mc-error').style.display = 'block';
document.getElementById('mc-results').style.display = 'none';
return;
}
// Defaults for optional fields if empty/NaN but not caught above
if (isNaN(annualTax)) annualTax = 0;
if (isNaN(annualIns)) annualIns = 0;
if (isNaN(monthlyHOA)) monthlyHOA = 0;
document.getElementById('mc-error').style.display = 'none';
// Calculations
var loanAmount = homePrice – downPayment;
// If down payment is greater than home price
if (loanAmount < 0) loanAmount = 0;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPI = 0;
// Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
if (interestRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) /
(Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns + monthlyHOA;
var totalCostOfLoan = (monthlyPI * numberOfPayments) + downPayment; // Total paid including downpayment, excluding tax/ins/hoa over time for simplicity of loan cost
var totalInterest = (monthlyPI * numberOfPayments) – loanAmount;
// Display Results
document.getElementById('mc-total-monthly').innerHTML = formatCurrency(totalMonthly);
document.getElementById('mc-pi').innerHTML = formatCurrency(monthlyPI);
document.getElementById('mc-tax-monthly').innerHTML = formatCurrency(monthlyTax);
document.getElementById('mc-ins-monthly').innerHTML = formatCurrency(monthlyIns);
document.getElementById('mc-hoa-monthly').innerHTML = formatCurrency(monthlyHOA);
document.getElementById('mc-loan-amount').innerHTML = formatCurrency(loanAmount);
document.getElementById('mc-total-interest').innerHTML = formatCurrency(totalInterest);
// Total cost usually refers to Principal + Interest
document.getElementById('mc-total-cost').innerHTML = formatCurrency(monthlyPI * numberOfPayments);
document.getElementById('mc-results').style.display = 'block';
}
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
30 Years
20 Years
15 Years
10 Years
Please enter valid positive numbers.
Monthly Payment: $0.00
Principal & Interest:
$0.00
Property Tax (Monthly):
$0.00
Home Insurance (Monthly):
$0.00
HOA Fees:
$0.00
Loan Amount:
$0.00
Total Interest Paid:
$0.00
Total Cost of Loan:
$0.00
Understanding Your Mortgage Payment
Calculating your potential monthly mortgage payment is a crucial first step in the home buying process. This Mortgage Payment Calculator helps you estimate your monthly costs by factoring in the loan principal, interest rate, property taxes, homeowner's insurance, and HOA fees.
Components of a Mortgage Payment (PITI)
Most lenders use the acronym PITI to describe the four main components of your monthly payment:
- Principal: The portion of your payment that goes toward paying down the loan balance (the amount you borrowed).
- Interest: The cost of borrowing money, paid to the lender. In the early years of a mortgage, a larger portion of your payment goes toward interest.
- Taxes: Property taxes assessed by your local government. These are often collected by the lender in an escrow account and paid annually on your behalf.
- Insurance: Homeowner's insurance protects your property against damage. Like taxes, this is usually bundled into your monthly payment via escrow.
How Interest Rate Affects Affordability
Even a small change in interest rates can significantly impact your monthly payment and the total interest paid over the life of the loan. For example, on a $300,000 loan, a 1% increase in interest rate can add hundreds of dollars to your monthly obligation and tens of thousands to the total cost of the loan.
Using the Calculator
To get the most accurate estimate, enter the home price and your planned down payment. Don't forget to include estimates for annual property taxes and insurance, as these can add 20-30% to your base principal and interest payment. If you are buying a condo or a home in a managed community, be sure to include Homeowners Association (HOA) fees.