.calculator-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.calc-header {
text-align: center;
margin-bottom: 30px;
border-bottom: 2px solid #0073aa;
padding-bottom: 10px;
}
.calc-header h1 {
color: #333;
margin: 0;
font-size: 28px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #555;
}
.input-wrapper {
position: relative;
display: flex;
align-items: center;
}
.input-wrapper input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
}
.currency-symbol, .percent-symbol {
position: absolute;
color: #777;
}
.currency-symbol { left: 10px; }
.percent-symbol { right: 10px; }
.with-currency input { padding-left: 25px; }
.with-percent input { padding-right: 25px; }
.calc-btn {
background-color: #0073aa;
color: white;
border: none;
padding: 12px 24px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #005177;
}
.results-section {
background-color: #f9f9f9;
padding: 20px;
border-radius: 6px;
margin-top: 20px;
border-left: 5px solid #0073aa;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
color: #555;
font-weight: 500;
}
.result-value {
color: #333;
font-weight: 700;
font-size: 18px;
}
.big-result {
font-size: 24px;
color: #0073aa;
}
.seo-content {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.seo-content h2 {
color: #23282d;
margin-top: 30px;
}
.seo-content ul {
padding-left: 20px;
}
.seo-content li {
margin-bottom: 10px;
}
function calculateMortgage() {
// 1. Get Input Values
var homePriceInput = document.getElementById('homePrice');
var downPaymentInput = document.getElementById('downPayment');
var interestRateInput = document.getElementById('interestRate');
var loanTermInput = document.getElementById('loanTerm');
var homePrice = parseFloat(homePriceInput.value);
var downPayment = parseFloat(downPaymentInput.value);
var annualRate = parseFloat(interestRateInput.value);
var termYears = parseFloat(loanTermInput.value);
// 2. Validate Inputs
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualRate) || isNaN(termYears)) {
alert("Please enter valid numbers in all fields.");
return;
}
if (homePrice <= 0 || termYears Home Price)
if (principal 0) {
if (annualRate === 0) {
// Simple division if interest is 0%
monthlyPayment = principal / numberOfPayments;
} else {
// Amortization Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var x = Math.pow(1 + monthlyRate, numberOfPayments);
monthlyPayment = (principal * x * monthlyRate) / (x – 1);
}
}
var totalCost = monthlyPayment * numberOfPayments;
var totalInterest = totalCost – principal;
// Calculate Payoff Date
var today = new Date();
var payoffDate = new Date(today.setMonth(today.getMonth() + numberOfPayments));
var payoffMonthYear = payoffDate.toLocaleString('default', { month: 'long', year: 'numeric' });
// 4. Update HTML Results
document.getElementById('monthlyPayment').innerText = formatCurrency(monthlyPayment);
document.getElementById('loanAmountResult').innerText = formatCurrency(principal);
document.getElementById('totalInterest').innerText = formatCurrency(totalInterest);
document.getElementById('totalCost').innerText = formatCurrency(totalCost);
document.getElementById('payoffDate').innerText = payoffMonthYear;
// Show results section
document.getElementById('results').style.display = 'block';
}
function formatCurrency(num) {
return new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(num);
}
Mortgage Payment Calculator
$
$
%
Monthly Principal & Interest:
$0.00
Loan Amount:
$0.00
Total Interest Paid:
$0.00
Total Cost of Loan:
$0.00
Payoff Date:
–
How to Calculate Your Mortgage Payments
Understanding your monthly mortgage obligation is the first step in the home-buying journey. This Mortgage Payment Calculator helps you estimate your monthly Principal and Interest (P&I) payments based on the home price, your down payment, the interest rate, and the loan term.
While this calculator provides the core payment amount, remember that your actual monthly bill ("PITI") often includes:
- Principal: The portion paying down the loan balance.
- Interest: The cost of borrowing the money.
- Taxes: Property taxes held in escrow by your lender.
- Insurance: Homeowners insurance premiums.
The Mortgage Formula Explained
Mortgages are calculated using a standard amortization formula. The math behind the numbers displayed above is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
- M = Total monthly payment
- P = Principal loan amount (Home Price minus Down Payment)
- i = Monthly interest rate (Annual Rate divided by 12)
- n = Number of payments (Loan Term in years multiplied by 12)
Factors That Affect Your Mortgage Payment
Several variables can significantly impact how much you pay each month and over the life of the loan:
- Down Payment: Putting more money down reduces the principal (P), which lowers both your monthly payment and the total interest paid. A down payment of 20% or more typically avoids Private Mortgage Insurance (PMI).
- Interest Rate: Even a fraction of a percentage point can change your payment by hundreds of dollars. Rates are influenced by your credit score, the economy, and the loan type.
- Loan Term: A 30-year term offers lower monthly payments but results in higher total interest costs. A 15-year term has higher monthly payments but saves significantly on interest.
Why Use This Calculator?
Before contacting a lender, it is crucial to run the numbers yourself. By adjusting the "Home Price" and "Down Payment" fields above, you can determine exactly how much house you can afford within your monthly budget. Use the results to plan your savings strategy or to decide between a 15-year and a 30-year fixed-rate mortgage.