Calculate your comprehensive monthly payment including Principal, Interest, Taxes, and Insurance.
Please enter valid numeric values for all fields.
Monthly Payment Breakdown
Principal & Interest:$0.00
Property Taxes:$0.00
Homeowners Insurance:$0.00
HOA Fees:$0.00
Total Monthly Payment (PITI):$0.00
Loan Summary:
Loan Amount: | Total Interest:
function calculatePITI() {
// 1. Get Elements
var homePriceInput = document.getElementById("homePrice");
var downPaymentInput = document.getElementById("downPayment");
var interestRateInput = document.getElementById("interestRate");
var loanTermInput = document.getElementById("loanTerm");
var propertyTaxInput = document.getElementById("propertyTax");
var homeInsuranceInput = document.getElementById("homeInsurance");
var hoaFeesInput = document.getElementById("hoaFees");
var resultBox = document.getElementById("resultBox");
var errorMsg = document.getElementById("errorMessage");
// 2. Parse Values
var homePrice = parseFloat(homePriceInput.value);
var downPayment = parseFloat(downPaymentInput.value);
var interestRate = parseFloat(interestRateInput.value);
var loanTerm = parseFloat(loanTermInput.value);
var annualTax = parseFloat(propertyTaxInput.value);
var annualInsurance = parseFloat(homeInsuranceInput.value);
var monthlyHOA = parseFloat(hoaFeesInput.value);
// Handle empty HOA as 0
if (isNaN(monthlyHOA)) {
monthlyHOA = 0;
}
// 3. Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(annualTax) || isNaN(annualInsurance)) {
errorMsg.style.display = "block";
resultBox.style.display = "none";
return;
}
// Check reasonable logic (Down payment shouldn't exceed home price)
if (downPayment >= homePrice) {
alert("Down payment cannot be greater than or equal to Home Price.");
return;
}
errorMsg.style.display = "none";
// 4. Calculation Logic
// Principal Amount
var principal = homePrice – downPayment;
// Monthly Interest Rate
var monthlyRate = (interestRate / 100) / 12;
// Total Number of Payments (Months)
var numberOfPayments = loanTerm * 12;
// Calculate Monthly Principal & Interest (P&I)
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
var x = Math.pow(1 + monthlyRate, numberOfPayments);
monthlyPI = (principal * x * monthlyRate) / (x – 1);
}
// Calculate Monthly Tax and Insurance
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
// Calculate Total PITI
var totalMonthly = monthlyPI + monthlyTax + monthlyInsurance + monthlyHOA;
// Calculate Total Cost of Loan logic
var totalRepayment = monthlyPI * numberOfPayments;
var totalInterest = totalRepayment – principal;
// 5. Display Results
document.getElementById("resPI").innerHTML = "$" + monthlyPI.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resTax").innerHTML = "$" + monthlyTax.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resIns").innerHTML = "$" + monthlyInsurance.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resHOA").innerHTML = "$" + monthlyHOA.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resTotal").innerHTML = "$" + totalMonthly.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resLoanAmount").innerHTML = "$" + principal.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
document.getElementById("resTotalInterest").innerHTML = "$" + totalInterest.toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
resultBox.style.display = "block";
}
Understanding Your PITI Mortgage Calculation
Buying a home is often the largest financial decision a person will make, but the sticker price of the house is only part of the story. To truly understand affordability, you must calculate the PITI—an acronym that stands for Principal, Interest, Taxes, and Insurance. These four components make up the bulk of your monthly mortgage obligation.
1. Principal
The principal is the portion of your payment that goes directly toward reducing the outstanding balance of your loan. In the early years of a standard amortization schedule, the principal portion is small, growing larger as time passes. Our calculator determines this by subtracting your down payment from the total home price.
2. Interest
Interest is the cost of borrowing money. This is paid to your lender as a percentage of the remaining principal balance. The interest rate you secure has a massive impact on your monthly payment. For example, on a $300,000 loan, a difference of just 1% in interest can change your monthly payment by hundreds of dollars and your total lifetime cost by tens of thousands.
3. Taxes (Property Taxes)
Real estate taxes are assessed by local governments to fund public services like schools, police, and road maintenance. Lenders typically collect 1/12th of your estimated annual tax bill every month and hold it in an escrow account to pay the government on your behalf. This calculator allows you to input your specific annual tax estimate to see exactly how it impacts your monthly budget.
4. Insurance
There are two main types of insurance often included in mortgage payments:
Homeowners Insurance: Protects your property against damage from fire, theft, and storms. Lenders require this to protect their collateral.
Private Mortgage Insurance (PMI): If your down payment is less than 20%, lenders may require PMI to protect them against default. While this calculator focuses on Homeowners Insurance, keep in mind that PMI may be an additional cost if you have a low down payment.
The Impact of HOA Fees
While not part of the "PITI" acronym strictly speaking, Homeowners Association (HOA) fees are a critical liability for condo owners or homes in planned communities. Since these are mandatory monthly fees, they directly reduce your purchasing power. We have included an HOA field in this calculator to ensure your "Total Monthly Payment" reflects reality.
How to Use This Mortgage Calculator
To get the most accurate result, follow these steps:
Enter Home Price: The listing price of the property or the amount you intend to offer.
Input Down Payment: The cash you are paying upfront. A higher down payment reduces your Principal and monthly interest costs.
Set Interest Rate: Check current market rates. Your credit score will heavily influence the rate you qualify for.
Define Loan Term: The standard is 30 years, but 15-year loans typically offer lower interest rates at the cost of higher monthly payments.
Estimate Taxes & Insurance: Look at the property's previous year tax records (often found on real estate listing sites) and get a quote for insurance.
Interpreting Your Results
Once you click "Calculate," review the breakdown. If the Total Monthly Payment exceeds 28% of your gross monthly income, lenders may view the loan as risky (known as the front-end ratio). Use this tool to adjust your home price budget or down payment savings goal until the monthly payment fits comfortably within your financial means.