Estimate your total monthly payment including taxes and insurance.
30 Years
20 Years
15 Years
10 Years
Total Monthly Payment
$0.00
Principal & Interest:$0.00
Property Tax:$0.00
Home Insurance:$0.00
HOA Fees:$0.00
PMI (Est.):$0.00
Loan Amount:$0.00
function calculateMortgage() {
// 1. Get Input Values
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var yearlyTax = parseFloat(document.getElementById("propertyTax").value);
var yearlyInsurance = parseFloat(document.getElementById("homeInsurance").value);
var monthlyHOA = parseFloat(document.getElementById("hoaFees").value);
// 2. Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTermYears)) {
alert("Please enter valid numbers for price, down payment, and interest rate.");
return;
}
// 3. Logic & Calculations
var loanAmount = homePrice – downPayment;
// Prevent negative loan amount
if (loanAmount 0 && monthlyRate > 0) {
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0) {
monthlyPI = loanAmount / numberOfPayments;
}
// Calculate Monthly Tax and Insurance
var monthlyTax = isNaN(yearlyTax) ? 0 : yearlyTax / 12;
var monthlyInsurance = isNaN(yearlyInsurance) ? 0 : yearlyInsurance / 12;
var hoa = isNaN(monthlyHOA) ? 0 : monthlyHOA;
// Calculate PMI (Private Mortgage Insurance)
// Logic: Typically required if Down Payment is less than 20% of Home Price.
// Approx 0.5% to 1% of loan amount yearly. We will use 0.5% as a standard estimation.
var pmi = 0;
var downPaymentPercent = (downPayment / homePrice) * 100;
if (downPaymentPercent 0) {
pmi = (loanAmount * 0.005) / 12;
}
// Total Monthly Payment
var totalMonthly = monthlyPI + monthlyTax + monthlyInsurance + hoa + pmi;
// 4. Output Display
// Helper to format currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById("totalMonthlyDisplay").innerHTML = formatter.format(totalMonthly);
document.getElementById("piDisplay").innerHTML = formatter.format(monthlyPI);
document.getElementById("taxDisplay").innerHTML = formatter.format(monthlyTax);
document.getElementById("insDisplay").innerHTML = formatter.format(monthlyInsurance);
document.getElementById("hoaDisplay").innerHTML = formatter.format(hoa);
document.getElementById("pmiDisplay").innerHTML = formatter.format(pmi);
document.getElementById("loanAmountDisplay").innerHTML = formatter.format(loanAmount);
// Show result section
document.getElementById("resultSection").style.display = "block";
}
Understanding Your Monthly Mortgage Payment (PITI)
When shopping for a home, many buyers focus solely on the principal and interest payment generated by standard loan calculators. However, the true cost of homeownership involves four key components known as PITI: Principal, Interest, Taxes, and Insurance.
1. Principal and Interest
This is the core of your mortgage payment. The Principal pays down the loan balance, while the Interest is the cost of borrowing money from your lender. In the early years of a standard 30-year fixed-rate mortgage, a larger portion of your payment goes toward interest. As time passes, more of your payment is applied to the principal.
2. Property Taxes
Real estate taxes are assessed by local governments to fund public services like schools, police, and road maintenance. These taxes vary significantly by location and are usually calculated as a percentage of your home's assessed value. Lenders often collect this money monthly and hold it in an escrow account to pay the tax bill on your behalf.
3. Homeowner's Insurance
Lenders require you to carry hazard insurance to protect the property against fire, theft, and other damages. Like property taxes, the premium is often divided into monthly installments and included in your mortgage payment.
4. HOA Fees and PMI
Beyond PITI, two other factors can affect your monthly outflow:
HOA Fees: If you buy a condo or a home in a planned community, you may owe Homeowners Association dues. These are usually paid directly to the association, but our calculator includes them to give you a complete picture of your housing expenses.
Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home price, lenders generally require PMI to protect them in case of default. This extra cost is added to your monthly bill until you build enough equity (usually 20%).
How to Use This Mortgage Calculator
To get the most accurate estimate, gather your financial details before starting:
Home Price: The listing price or your offer amount.
Down Payment: Cash you are paying upfront. A higher down payment reduces your loan amount and may eliminate PMI.
Interest Rate: Check current market rates. Your credit score will heavily influence the rate you are offered.
Taxes & Insurance: Look at the property listing for the most recent tax year data and estimate insurance costs (typically $60-$120 per month depending on coverage).
By inputting these specific figures into the calculator above, you can determine if a specific property fits within your monthly budget.