.calc-section { margin-bottom: 20px; }
.calc-label { display: block; font-weight: 600; margin-bottom: 8px; color: #333; font-size: 14px; }
.calc-input-wrapper { position: relative; }
.calc-input { width: 100%; padding: 12px; border: 2px solid #edeff2; border-radius: 8px; font-size: 16px; box-sizing: border-box; transition: border-color 0.3s ease; }
.calc-input:focus { outline: none; border-color: #007cba; }
.calc-button { width: 100%; background-color: #007cba; color: white; padding: 15px; border: none; border-radius: 8px; font-size: 18px; font-weight: 700; cursor: pointer; transition: background-color 0.3s ease; margin-top: 10px; }
.calc-button:hover { background-color: #0067a3; }
#mortgage-result { margin-top: 25px; padding: 20px; border-radius: 8px; background-color: #f7f9fa; display: none; border-left: 5px solid #007cba; }
.result-value { font-size: 32px; font-weight: 800; color: #007cba; margin: 10px 0; }
.result-detail { font-size: 14px; color: #666; line-height: 1.6; }
.mortgage-article { margin-top: 40px; border-top: 1px solid #eee; padding-top: 30px; line-height: 1.8; color: #444; }
.mortgage-article h2 { color: #222; font-size: 24px; margin-bottom: 15px; }
.mortgage-article h3 { color: #333; font-size: 20px; margin-top: 25px; }
.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 600px) { .calc-grid { grid-template-columns: 1fr; } }
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById('homePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var annualRate = parseFloat(document.getElementById('interestRate').value);
var loanTermYears = parseFloat(document.getElementById('loanTerm').value);
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualRate) || homePrice <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
var loanAmount = homePrice – downPayment;
if (loanAmount <= 0) {
alert("Down payment cannot be greater than or equal to the home price.");
return;
}
var monthlyRate = (annualRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPayment = 0;
// If interest rate is 0, simple division
if (annualRate === 0) {
monthlyPayment = loanAmount / numberOfPayments;
} else {
var x = Math.pow(1 + monthlyRate, numberOfPayments);
monthlyPayment = (loanAmount * x * monthlyRate) / (x – 1);
}
var totalRepayment = monthlyPayment * numberOfPayments;
var totalInterest = totalRepayment – loanAmount;
// Format numbers to currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('monthly-payment-output').innerHTML = formatter.format(monthlyPayment);
document.getElementById('total-repayment-output').innerHTML = "Total of " + numberOfPayments + " payments: " + formatter.format(totalRepayment);
document.getElementById('total-interest-output').innerHTML = "Total Interest Paid: " + formatter.format(totalInterest);
document.getElementById('mortgage-result').style.display = 'block';
// Smooth scroll to result for mobile
document.getElementById('mortgage-result').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}
Mortgage Monthly Payment Calculator
30 Years
20 Years
15 Years
10 Years
Your Estimated Monthly Payment:
$0.00
How to Use the Mortgage Payment Calculator
Planning to buy a home is one of the most significant financial decisions you will ever make. Our Mortgage Payment Calculator helps you estimate your monthly principal and interest costs instantly. To get an accurate estimate, you need four key pieces of information:
- Home Price: The total purchase price of the property you intend to buy.
- Down Payment: The amount of cash you pay upfront. A higher down payment reduces your loan amount and monthly interest.
- Interest Rate: The annual percentage rate (APR) charged by your lender. Even a 0.5% difference can save you tens of thousands of dollars over the life of the loan.
- Loan Term: The duration of the loan. Most residential mortgages in the United States are for 30 years, though 15-year terms are popular for those who want to pay off debt faster.
The Mortgage Calculation Formula
Financial institutions use a specific amortization formula to determine your monthly payment (P). The formula is expressed as:
P = L [ c(1 + c)^n ] / [ (1 + c)^n – 1 ]
Where:
- L = Loan amount (Home Price – Down Payment)
- c = Monthly interest rate (Annual Rate / 12)
- n = Total number of payments (Years x 12)
Example Calculation
Suppose you purchase a home for $400,000 with a 20% down payment ($80,000). This leaves you with a loan amount of $320,000. At a fixed interest rate of 6.5% for a 30-year term:
- The monthly interest rate is 0.065 / 12 = 0.005416.
- The total number of payments is 30 x 12 = 360.
- Your monthly principal and interest payment would be approximately $2,022.62.
- Over 30 years, you would pay a total of $728,143, consisting of $320,000 in principal and $408,143 in interest.
Important Factors to Consider
While this calculator provides the base monthly payment (Principal and Interest), your actual housing cost might include other expenses such as:
- Property Taxes: Usually assessed annually by your local government and often rolled into your monthly mortgage payment via escrow.
- Homeowners Insurance: Lenders require insurance to protect the asset.
- Private Mortgage Insurance (PMI): Typically required if your down payment is less than 20%.
- HOA Fees: Homeowners Association dues if you buy in a managed community or condo.