.calc-container {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.calc-box {
background: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
font-weight: 600;
margin-bottom: 5px;
font-size: 14px;
}
.input-wrapper {
position: relative;
}
.input-wrapper span {
position: absolute;
left: 10px;
top: 50%;
transform: translateY(-50%);
color: #666;
}
.input-wrapper input {
width: 100%;
padding: 10px 10px 10px 25px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-wrapper input:focus {
border-color: #007bff;
outline: none;
}
.input-wrapper.percentage input {
padding: 10px 25px 10px 10px;
}
.input-wrapper.percentage span {
left: auto;
right: 10px;
}
.calc-btn {
background-color: #007bff;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #0056b3;
}
#calc-results {
margin-top: 30px;
display: none;
border-top: 2px solid #e9ecef;
padding-top: 20px;
}
.result-card {
background: #fff;
padding: 20px;
border-radius: 6px;
border: 1px solid #ddd;
text-align: center;
margin-bottom: 20px;
}
.result-value-big {
font-size: 36px;
font-weight: 800;
color: #28a745;
margin: 10px 0;
}
.result-details {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
text-align: left;
}
.detail-item {
background: #fff;
padding: 10px;
border-radius: 4px;
border: 1px solid #eee;
}
.detail-label {
font-size: 13px;
color: #666;
}
.detail-val {
font-weight: bold;
font-size: 16px;
}
.calc-article h2 {
margin-top: 30px;
color: #2c3e50;
border-bottom: 2px solid #007bff;
padding-bottom: 10px;
display: inline-block;
}
.calc-article h3 {
color: #34495e;
margin-top: 25px;
}
.calc-article p, .calc-article li {
color: #555;
font-size: 17px;
}
.error-msg {
color: red;
font-weight: bold;
display: none;
text-align: center;
margin-top: 10px;
}
function calculateMortgage() {
// Get inputs
var homePrice = parseFloat(document.getElementById('mc_homePrice').value);
var downPayment = parseFloat(document.getElementById('mc_downPayment').value);
var interestRate = parseFloat(document.getElementById('mc_interestRate').value);
var loanTerm = parseFloat(document.getElementById('mc_loanTerm').value);
var propertyTax = parseFloat(document.getElementById('mc_propertyTax').value);
var insurance = parseFloat(document.getElementById('mc_insurance').value);
var hoa = parseFloat(document.getElementById('mc_hoa').value);
var errorDiv = document.getElementById('mc_error');
var resultsDiv = document.getElementById('calc-results');
// Reset error
errorDiv.style.display = 'none';
resultsDiv.style.display = 'none';
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) ||
homePrice <= 0 || loanTerm <= 0) {
errorDiv.style.display = 'block';
return;
}
// Calculations
var principal = homePrice – downPayment;
// Handle negative principal
if (principal < 0) {
principal = 0;
}
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
monthlyPI = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
if (isNaN(monthlyPI) || !isFinite(monthlyPI)) {
monthlyPI = 0;
}
var monthlyTax = isNaN(propertyTax) ? 0 : propertyTax / 12;
var monthlyIns = isNaN(insurance) ? 0 : insurance / 12;
var monthlyHOA = isNaN(hoa) ? 0 : hoa;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns + monthlyHOA;
var totalInterest = (monthlyPI * numberOfPayments) – principal;
// Payoff Date
var today = new Date();
var payoffYear = today.getFullYear() + loanTerm;
var monthName = today.toLocaleString('default', { month: 'short' });
var payoffDateString = monthName + " " + payoffYear;
// Update UI
function formatMoney(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
document.getElementById('mc_totalMonthly').innerText = formatMoney(totalMonthly);
document.getElementById('mc_pi').innerText = formatMoney(monthlyPI);
document.getElementById('mc_monthlyTax').innerText = formatMoney(monthlyTax);
document.getElementById('mc_monthlyIns').innerText = formatMoney(monthlyIns);
document.getElementById('mc_loanAmount').innerText = formatMoney(principal);
document.getElementById('mc_totalInterest').innerText = formatMoney(totalInterest);
document.getElementById('mc_payoffDate').innerText = payoffDateString;
resultsDiv.style.display = 'block';
}
Understanding Your Mortgage Calculation
Purchasing a home is likely the largest financial commitment you will ever make. Using this Mortgage Calculator helps you break down the monthly costs associated with homeownership, ensuring you stick to your budget. Beyond just the loan repayment, true homeownership costs include property taxes, insurance, and potential HOA fees.
How is the Monthly Payment Calculated?
Your total monthly mortgage payment is composed of four main parts, often referred to as PITI:
- Principal: The portion of your payment that goes toward paying down the loan balance ($).
- Interest: The fee charged by the lender for borrowing the money. In the early years of a standard amortization schedule, the majority of your payment goes toward interest.
- Taxes: Property taxes collected by your local government. These are typically held in an escrow account and paid annually by your servicer.
- Insurance: Homeowners insurance protects your property against damage. Like taxes, this is usually bundled into your monthly payment via escrow.
The Impact of Interest Rates
Even a small change in your interest rate can have a massive impact on your monthly payment and the total cost of the loan. For example, on a $300,000 loan, a 1% difference in interest rate can save or cost you tens of thousands of dollars over a 30-year term. It is crucial to shop around for the best rate before signing.
Fixed vs. Adjustable Rate Mortgages
This calculator assumes a Fixed-Rate Mortgage, where the interest rate remains the same for the life of the loan. This provides stability and predictability. Conversely, an Adjustable-Rate Mortgage (ARM) has a rate that may change after an initial fixed period, potentially increasing your monthly obligation significantly.
Frequently Asked Questions
What is an escrow account?
An escrow account is a savings account managed by your mortgage servicer. Your monthly payments include extra money for taxes and insurance, which the lender deposits into this account to pay those bills when they are due.
Does this calculator include PMI?
Private Mortgage Insurance (PMI) is typically required if your down payment is less than 20%. While this calculator includes taxes and insurance, PMI rates vary widely based on credit score. If you are putting down less than 20%, anticipate an additional cost of 0.5% to 1% of the loan amount annually.