30 Years Fixed
20 Years Fixed
15 Years Fixed
10 Years Fixed
Your Estimated Monthly Payment
$0.00
Total Loan Amount
$0.00
Total Interest Paid
$0.00
Total Cost of Loan
$0.00
Down Payment %
0%
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 calculator helps you estimate your monthly principal and interest payments so you can budget effectively. To get an accurate estimate, follow these steps:
Home Price: Enter the total purchase price of the property you wish to buy.
Down Payment: Enter the amount of cash you plan to pay upfront. A 20% down payment is traditional to avoid Private Mortgage Insurance (PMI).
Interest Rate: Enter the annual interest rate. Even a 0.5% difference can save you tens of thousands of dollars over the life of the loan.
Loan Term: Choose the duration of the loan. 30-year fixed-rate mortgages are most common, but 15-year options often offer lower interest rates.
Understanding the Mortgage Formula
The calculator uses the standard fixed-rate mortgage formula to determine your monthly payment (M):
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
Where P is the principal loan amount, i is the monthly interest rate (annual rate divided by 12), and n is the total number of months in the loan term.
Example Calculation
If you purchase a home for $400,000 with a $80,000 down payment (20%), your loan amount is $320,000. At a 6.5% interest rate over 30 years:
Monthly Principal & Interest: $2,022.62
Total Interest Paid over 30 years: $408,144.38
Total Cost of Loan: $728,144.38
Note: This calculator estimates principal and interest. It does not include property taxes, homeowners insurance, or HOA fees, which are typically held in an escrow account by your lender.
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var annualInterest = parseFloat(document.getElementById("interestRate").value);
var years = parseInt(document.getElementById("loanTerm").value);
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualInterest) || isNaN(years)) {
alert("Please enter valid numbers in all fields.");
return;
}
var principal = homePrice – downPayment;
if (principal <= 0) {
alert("Down payment cannot be equal to or greater than the home price.");
return;
}
var monthlyInterest = (annualInterest / 100) / 12;
var numberOfPayments = years * 12;
var monthlyPayment = 0;
if (monthlyInterest === 0) {
monthlyPayment = principal / numberOfPayments;
} else {
var x = Math.pow(1 + monthlyInterest, numberOfPayments);
monthlyPayment = (principal * x * monthlyInterest) / (x – 1);
}
var totalCost = monthlyPayment * numberOfPayments;
var totalInterest = totalCost – principal;
var downPercent = (downPayment / homePrice) * 100;
document.getElementById("monthlyPaymentDisplay").innerHTML = "$" + monthlyPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalLoanAmount").innerHTML = "$" + principal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalInterestPaid").innerHTML = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalCostOfLoan").innerHTML = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("downPaymentPercent").innerHTML = downPercent.toFixed(1) + "%";
document.getElementById("mortgageResult").style.display = "block";
}