.seo-calculator-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #ffffff;
border: 1px solid #e2e8f0;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.calc-header {
text-align: center;
margin-bottom: 30px;
}
.calc-header h2 {
margin: 0;
color: #2d3748;
font-size: 28px;
}
.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;
margin-bottom: 8px;
font-weight: 600;
color: #4a5568;
font-size: 14px;
}
.input-wrapper {
position: relative;
}
.input-wrapper input {
width: 100%;
padding: 12px;
padding-left: 12px;
border: 1px solid #cbd5e0;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.2s;
}
.input-wrapper input:focus {
border-color: #4299e1;
outline: none;
box-shadow: 0 0 0 3px rgba(66, 153, 225, 0.2);
}
.input-symbol {
position: absolute;
right: 12px;
top: 50%;
transform: translateY(-50%);
color: #718096;
}
.calc-btn {
grid-column: 1 / -1;
background-color: #4299e1;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
width: 100%;
}
.calc-btn:hover {
background-color: #3182ce;
}
.results-section {
margin-top: 30px;
padding: 25px;
background-color: #f7fafc;
border-radius: 8px;
border: 1px solid #edf2f7;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 15px;
padding-bottom: 15px;
border-bottom: 1px solid #e2e8f0;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
color: #4a5568;
font-weight: 500;
}
.result-value {
font-size: 20px;
font-weight: bold;
color: #2d3748;
}
.result-main {
text-align: center;
margin-bottom: 25px;
padding-bottom: 20px;
border-bottom: 2px solid #cbd5e0;
}
.result-main .result-value {
font-size: 42px;
color: #2b6cb0;
}
.result-main .result-label {
font-size: 16px;
text-transform: uppercase;
letter-spacing: 1px;
color: #718096;
}
.seo-content {
margin-top: 50px;
line-height: 1.6;
color: #2d3748;
}
.seo-content h3 {
color: #2c5282;
margin-top: 25px;
border-bottom: 2px solid #e2e8f0;
padding-bottom: 10px;
}
.seo-content p {
margin-bottom: 15px;
}
.seo-content ul {
margin-bottom: 15px;
padding-left: 20px;
}
.seo-content li {
margin-bottom: 8px;
}
.error-msg {
color: #e53e3e;
text-align: center;
margin-top: 10px;
display: none;
}
function calculateMortgage() {
// Get input values
var homePrice = parseFloat(document.getElementById('mc-home-price').value);
var downPayment = parseFloat(document.getElementById('mc-down-payment').value);
var interestRate = parseFloat(document.getElementById('mc-interest-rate').value);
var loanTerm = parseFloat(document.getElementById('mc-loan-term').value);
var errorDiv = document.getElementById('mc-error');
var resultsDiv = document.getElementById('mc-results');
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) ||
homePrice <= 0 || loanTerm <= 0 || interestRate < 0 || downPayment < 0) {
errorDiv.style.display = 'block';
resultsDiv.style.display = 'none';
return;
}
errorDiv.style.display = 'none';
// Calculations
var principal = homePrice – downPayment;
// Handle edge case where principal is 0 or negative
if (principal <= 0) {
document.getElementById('mc-monthly-payment').innerText = "$0.00";
document.getElementById('mc-principal-amount').innerText = "$0.00";
document.getElementById('mc-total-interest').innerText = "$0.00";
document.getElementById('mc-total-cost').innerText = "$0.00";
resultsDiv.style.display = 'block';
return;
}
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
var monthlyPayment = 0;
// Handle 0% interest rate edge case
if (interestRate === 0) {
monthlyPayment = principal / numberOfPayments;
} else {
// Standard 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;
// Update UI with Formatted Numbers
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2,
maximumFractionDigits: 2
});
document.getElementById('mc-monthly-payment').innerText = formatter.format(monthlyPayment);
document.getElementById('mc-principal-amount').innerText = formatter.format(principal);
document.getElementById('mc-total-interest').innerText = formatter.format(totalInterest);
document.getElementById('mc-total-cost').innerText = formatter.format(totalCost);
// Show results
resultsDiv.style.display = 'block';
}
Mortgage Payment Calculator
Estimate your monthly mortgage payments including principal and interest.
%
Yrs
Please enter valid positive numbers for all fields.
Estimated Monthly Payment
$0.00
Loan Amount (Principal)
$0.00
Total Interest Paid
$0.00
Total Cost of Loan
$0.00
How Your Mortgage Payment is Calculated
Understanding the components of your monthly mortgage payment is crucial for financial planning when buying a home. This calculator uses the standard amortization formula to determine exactly how much you will owe the lender each month based on four key factors:
- Home Price: The total purchase price of the real estate.
- Down Payment: The upfront cash you pay toward the home. A larger down payment reduces the principal loan amount and the interest you pay over time.
- Interest Rate: The annual percentage rate (APR) charged by the lender. Even a small difference of 0.5% can save or cost you tens of thousands of dollars over the life of a loan.
- Loan Term: The duration of the loan, typically 15 or 30 years in the United States. Shorter terms usually have lower interest rates but higher monthly payments.
The Impact of Interest Rates on Affordability
Interest rates are the single biggest variable in the cost of borrowing. When rates are high, your buying power decreases because a larger portion of your monthly budget goes toward interest rather than equity. For example, on a $300,000 loan, the difference between a 4% and a 7% interest rate changes the monthly payment by several hundred dollars, significantly affecting your debt-to-income ratio.
Principal vs. Interest Over Time
Mortgages use an amortization schedule. In the early years of your loan, the majority of your payment goes toward paying off interest. As time passes and the principal balance decreases, a larger portion of your payment goes toward principal. This is why building equity can feel slow in the first 5-7 years of a standard 30-year mortgage.
Beyond Principal and Interest
While this calculator focuses on Principal and Interest (P&I), remember that your actual monthly housing expense will likely include Property Taxes, Homeowners Insurance, and potentially Private Mortgage Insurance (PMI) if your down payment is less than 20%. It is recommended to budget an additional 25-30% above the P&I figure to cover these escrow items.