.amc-row { display: flex; flex-wrap: wrap; margin: 0 -10px; }
.amc-col { flex: 1; min-width: 250px; padding: 0 10px; margin-bottom: 15px; }
.amc-label { display: block; margin-bottom: 5px; font-weight: 600; color: #333; font-size: 14px; }
.amc-input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; font-size: 16px; box-sizing: border-box; }
.amc-input:focus { border-color: #0073aa; outline: none; }
.amc-btn { background-color: #0073aa; color: white; padding: 12px 20px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; width: 100%; font-weight: bold; transition: background 0.3s; }
.amc-btn:hover { background-color: #005177; }
.amc-result-box { background: #f9f9f9; border: 1px solid #ddd; padding: 20px; border-radius: 6px; margin-top: 20px; }
.amc-result-row { display: flex; justify-content: space-between; margin-bottom: 10px; font-size: 15px; border-bottom: 1px dotted #ccc; padding-bottom: 5px; }
.amc-result-row:last-child { border-bottom: none; }
.amc-result-label { color: #555; }
.amc-result-value { font-weight: bold; color: #222; }
.amc-total-payment { font-size: 24px; color: #2ecc71; font-weight: 800; text-align: center; margin-bottom: 20px; }
.amc-error { color: red; font-size: 14px; display: none; margin-top: 10px; text-align: center; }
@media (max-width: 600px) {
.amc-col { min-width: 100%; }
}
function calculateMortgage() {
// Get Input Values
var price = parseFloat(document.getElementById('homePrice').value);
var down = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseInt(document.getElementById('loanTerm').value);
var taxYear = parseFloat(document.getElementById('propertyTax').value);
var insYear = parseFloat(document.getElementById('homeInsurance').value);
var pmiMonth = parseFloat(document.getElementById('pmi').value);
var hoaMonth = parseFloat(document.getElementById('hoa').value);
// Error Handling for Empty/Invalid Inputs
if (isNaN(price) || isNaN(down) || isNaN(rate) || isNaN(years)) {
document.getElementById('amcError').style.display = 'block';
document.getElementById('amcResults').style.display = 'none';
return;
}
// Handle optional fields defaulting to 0 if empty/NaN
if (isNaN(taxYear)) taxYear = 0;
if (isNaN(insYear)) insYear = 0;
if (isNaN(pmiMonth)) pmiMonth = 0;
if (isNaN(hoaMonth)) hoaMonth = 0;
document.getElementById('amcError').style.display = 'none';
// Calculations
var principal = price – down;
if (principal <= 0) {
document.getElementById('amcError').innerText = "Down payment cannot equal or exceed Home Price.";
document.getElementById('amcError').style.display = 'block';
document.getElementById('amcResults').style.display = 'none';
return;
}
var monthlyRate = rate / 100 / 12;
var numPayments = years * 12;
// Standard Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var monthlyPI = 0;
if (rate === 0) {
monthlyPI = principal / numPayments;
} else {
monthlyPI = principal * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
var monthlyTax = taxYear / 12;
var monthlyIns = insYear / 12;
var monthlyTotal = monthlyPI + monthlyTax + monthlyIns + pmiMonth + hoaMonth;
var totalInterest = (monthlyPI * numPayments) – principal;
// Update DOM
var currencyFormatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById('totalMonthlyPayment').innerHTML = currencyFormatter.format(monthlyTotal);
document.getElementById('resPrincipalInterest').innerHTML = currencyFormatter.format(monthlyPI);
document.getElementById('resTax').innerHTML = currencyFormatter.format(monthlyTax);
document.getElementById('resInsurance').innerHTML = currencyFormatter.format(monthlyIns);
document.getElementById('resPmiHoa').innerHTML = currencyFormatter.format(pmiMonth + hoaMonth);
document.getElementById('resLoanAmount').innerHTML = currencyFormatter.format(principal);
document.getElementById('resTotalInterest').innerHTML = currencyFormatter.format(totalInterest);
document.getElementById('amcResults').style.display = 'block';
}
Advanced Mortgage Calculator (PITI)
30 Years
20 Years
15 Years
10 Years
Please enter valid numeric values for all fields.
Estimated Monthly Payment
$0.00
Principal & Interest:
$0.00
Property Tax (Monthly):
$0.00
Home Insurance (Monthly):
$0.00
PMI & HOA:
$0.00
Loan Amount:
$0.00
Total Interest Paid (Over Term):
$0.00
Understanding Your Total Monthly Mortgage Payment
Buying a home is one of the most significant financial decisions you will make. While the listing price gives you a general idea of the cost, your actual monthly obligation involves several distinct components. Our Advanced Mortgage Calculator helps you break down the "PITI" (Principal, Interest, Taxes, and Insurance) to give you a realistic view of affordability.
What is Included in PITI?
Lenders use the PITI acronym to calculate your debt-to-income ratio. Here is what each letter represents:
- Principal: The portion of your payment that pays down the loan balance. In the early years of a 30-year mortgage, this amount is small but grows over time.
- Interest: The cost of borrowing money. This is calculated based on your annual interest rate and remaining loan balance.
- Taxes: Property taxes assessed by your local government. These are typically held in an escrow account by your lender and paid annually or semi-annually on your behalf.
- Insurance: Homeowners insurance protects your property against damage. Like taxes, this is usually bundled into your monthly payment via escrow.
The Impact of PMI and HOA Dues
Beyond PITI, two other factors can significantly increase your monthly outlay:
- Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's value, lenders usually require PMI to protect them against default. This does not pay off your loan or protect you; it is a pure cost added to your monthly bill.
- Homeowners Association (HOA) Fees: If you buy a condo or a home in a planned community, you will likely owe monthly or quarterly dues. While not paid to the lender, these are mandatory costs that impact your cash flow and mortgage qualification.
How to Lower Your Monthly Payment
If the result from the calculator is higher than your budget allows, consider these strategies:
- Increase your Down Payment: This lowers the principal loan amount and may eliminate the need for PMI.
- Shop for Lower Interest Rates: Even a 0.5% difference can save tens of thousands of dollars over the life of the loan.
- Consider a Longer Term: While a 15-year loan saves on interest, a 30-year loan will have significantly lower monthly payments.
Use the calculator above to experiment with different home prices, down payments, and interest rates to find the mortgage setup that fits your financial goals perfectly.