:root {
–primary-color: #2c3e50;
–accent-color: #27ae60;
–bg-color: #f4f7f6;
–text-color: #333;
–border-radius: 8px;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: var(–text-color);
max-width: 1000px;
margin: 0 auto;
padding: 20px;
background-color: #fff;
}
.calc-wrapper {
background: var(–bg-color);
padding: 30px;
border-radius: var(–border-radius);
box-shadow: 0 4px 6px rgba(0,0,0,0.1);
margin-bottom: 40px;
border: 1px solid #e0e0e0;
}
.calc-header {
text-align: center;
margin-bottom: 25px;
}
.calc-header h2 {
margin: 0;
color: var(–primary-color);
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 768px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 0.9em;
color: var(–primary-color);
}
.input-group input, .input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: var(–accent-color);
outline: none;
}
.calc-btn {
grid-column: 1 / -1;
background-color: var(–accent-color);
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.3s;
margin-top: 10px;
width: 100%;
}
.calc-btn:hover {
background-color: #219150;
}
.results-section {
grid-column: 1 / -1;
background: #fff;
padding: 20px;
border-radius: var(–border-radius);
margin-top: 20px;
border-left: 5px solid var(–accent-color);
display: none; /* Hidden by default */
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-row.total {
font-size: 1.2em;
font-weight: bold;
color: var(–accent-color);
border-top: 2px solid #eee;
margin-top: 10px;
padding-top: 15px;
}
.error-msg {
color: #e74c3c;
text-align: center;
margin-top: 10px;
display: none;
font-weight: bold;
}
/* Article Styles */
.content-article h2 {
color: var(–primary-color);
border-bottom: 2px solid var(–accent-color);
padding-bottom: 10px;
margin-top: 40px;
}
.content-article h3 {
color: #34495e;
margin-top: 25px;
}
.content-article p, .content-article li {
color: #555;
font-size: 1.05em;
}
.content-article ul {
padding-left: 20px;
}
.info-box {
background-color: #e8f6f3;
padding: 15px;
border-radius: 4px;
margin: 20px 0;
border-left: 4px solid var(–accent-color);
}
Understanding Your Monthly Mortgage Payment (PITI)
When shopping for a home, many buyers focus solely on the listing price and the interest rate. However, the actual check you write every month—often referred to as PITI—includes several other critical components. Using a comprehensive mortgage calculator is essential to budget accurately and avoid "payment shock" after closing.
What is Included in PITI?
PITI stands for Principal, Interest, Taxes, and Insurance. These are the four standard components of a monthly mortgage payment:
- Principal: The portion of your payment that goes toward paying 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 paid to your lender. Initially, interest makes up the bulk of your monthly payment.
- Taxes: Property taxes assessed by your local government. Lenders typically collect 1/12th of your estimated annual tax bill each month and hold it in an escrow account.
- Insurance: Homeowners insurance covers damages to your property. Like taxes, this is usually escrowed monthly.
Expert Tip: Don't forget HOA fees! If you are buying a condo or a home in a planned community, Homeowners Association (HOA) dues are paid separately from your mortgage but significantly impact your monthly affordability. Our calculator includes a field for HOA to give you the full picture.
How Down Payment Affects Your Loan
The size of your down payment plays a pivotal role in your financial health. Putting down at least 20% of the home price generally allows you to avoid Private Mortgage Insurance (PMI), a monthly fee that protects the lender, not you. If your down payment is less than 20%, you should factor an additional 0.5% to 1% of the loan amount annually into your budget for PMI costs.
The Impact of Interest Rates
Even a small fluctuation in interest rates can drastically change your buying power. For a $400,000 loan, the difference between a 6% and a 7% interest rate is roughly $260 per month. Over the life of a 30-year loan, that single percentage point costs you over $93,000 in additional interest.
Using This Calculator
To get the most accurate result, try to find the exact property tax rate for the county where you are looking to buy. Property taxes can range widely, from under 0.5% to over 2.5% of the home's assessed value depending on the location. Input your estimated insurance costs and HOA fees to see the "out the door" monthly cost of homeownership.
Frequently Asked Questions
Does this calculator include closing costs?
No, this calculator estimates your recurring monthly expenses. Closing costs are one-time fees paid at the signing of the mortgage, typically ranging from 2% to 5% of the loan amount.
Why is my Principal payment so low?
This is due to amortization. In the beginning of a long-term loan, the majority of your payment covers the interest accrued. As the loan balance decreases, less interest accrues, and more of your fixed payment is applied to the principal.
// Set default Start Date to current month
var today = new Date();
var yyyy = today.getFullYear();
var mm = String(today.getMonth() + 1).padStart(2, '0');
document.getElementById('startDate').value = yyyy + '-' + mm;
function calculateMortgage() {
// 1. Get Inputs
var homePrice = parseFloat(document.getElementById('homePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanTermYears = parseFloat(document.getElementById('loanTerm').value);
var propertyTaxAnnual = parseFloat(document.getElementById('propertyTax').value);
var homeInsuranceAnnual = parseFloat(document.getElementById('homeInsurance').value);
var hoaFeesMonthly = parseFloat(document.getElementById('hoaFees').value);
// 2. Element Handles for Output
var resPI = document.getElementById('res-pi');
var resTax = document.getElementById('res-tax');
var resIns = document.getElementById('res-ins');
var resHoa = document.getElementById('res-hoa');
var resTotal = document.getElementById('res-total');
var resLoanAmt = document.getElementById('res-loan-amount');
var resTotalInt = document.getElementById('res-total-interest');
var errorBox = document.getElementById('error-message');
var resultsBox = document.getElementById('results');
// 3. Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(propertyTaxAnnual) || isNaN(homeInsuranceAnnual)) {
errorBox.style.display = 'block';
resultsBox.style.display = 'none';
return;
}
if (isNaN(hoaFeesMonthly)) {
hoaFeesMonthly = 0; // Default to 0 if empty
}
// Hide error if valid
errorBox.style.display = 'none';
resultsBox.style.display = 'block';
// 4. Calculations
var principal = homePrice – downPayment;
// Handle case where downpayment > price
if (principal < 0) principal = 0;
var monthlyInterestRate = (interestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
// Mortgage 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 + monthlyInterestRate, numberOfPayments);
monthlyPI = (principal * x * monthlyInterestRate) / (x – 1);
}
var monthlyTax = propertyTaxAnnual / 12;
var monthlyInsurance = homeInsuranceAnnual / 12;
var totalMonthlyPayment = monthlyPI + monthlyTax + monthlyInsurance + hoaFeesMonthly;
var totalLifetimePayment = monthlyPI * numberOfPayments;
var totalInterest = totalLifetimePayment – principal;
// 5. Formatting and Display
var currencyFormatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
resPI.innerHTML = currencyFormatter.format(monthlyPI);
resTax.innerHTML = currencyFormatter.format(monthlyTax);
resIns.innerHTML = currencyFormatter.format(monthlyInsurance);
resHoa.innerHTML = currencyFormatter.format(hoaFeesMonthly);
resTotal.innerHTML = currencyFormatter.format(totalMonthlyPayment);
resLoanAmt.innerHTML = currencyFormatter.format(principal);
resTotalInt.innerHTML = currencyFormatter.format(totalInterest);
}