Understanding loan amortization is crucial for any borrower. An amortization schedule breaks down your loan payment into principal and interest components over time. Initially, a larger portion of your payment goes towards interest, but as you pay down the principal, more of your payment will be applied to the principal, reducing the total interest paid and the loan's life.
This Loan Amortization Calculator will help you visualize how your loan will be paid off over its term. By entering the loan amount, interest rate, and loan term, you can see a detailed breakdown of each payment, including the principal and interest portions, and the remaining balance. This tool is invaluable for budgeting, comparing loan offers, and making informed financial decisions.
Loan Amortization Calculator
function calculateAmortization() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTermYears").value);
var resultDiv = document.getElementById("amortizationResult");
var tableDiv = document.getElementById("amortizationTable");
resultDiv.innerHTML = "";
tableDiv.innerHTML = "";
if (isNaN(loanAmount) || isNaN(annualInterestRate) || isNaN(loanTermYears) || loanAmount <= 0 || annualInterestRate < 0 || loanTermYears <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
var monthlyInterestRate = annualInterestRate / 12 / 100;
var numberOfPayments = loanTermYears * 12;
// Calculate monthly payment using the loan payment formula:
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
// Where:
// M = Monthly Payment
// P = Principal Loan Amount
// i = Monthly Interest Rate
// n = Total Number of Payments (loan term in months)
var monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
// Handle cases where the interest rate is 0
if (monthlyInterestRate === 0) {
monthlyPayment = loanAmount / numberOfPayments;
}
var totalInterestPaid = (monthlyPayment * numberOfPayments) – loanAmount;
var totalAmountPaid = monthlyPayment * numberOfPayments;
resultDiv.innerHTML = "
" +
"" +
"";
var remainingBalance = loanAmount;
var currentDate = new Date(); // Start date for payments
for (var i = 1; i remainingBalance) {
principalPayment = remainingBalance;
monthlyPayment = principalPayment + interestPayment; // Adjust monthly payment for the last payment
}
remainingBalance -= principalPayment;
// Format date to be approximately monthly
var paymentDate = new Date(currentDate);
paymentDate.setMonth(currentDate.getMonth() + i -1);
var formattedDate = (paymentDate.getMonth() + 1) + "/" + paymentDate.getDate() + "/" + paymentDate.getFullYear();
tableHTML += "
" +
"
" + i + "
" +
"
" + formattedDate + "
" +
"
$" + principalPayment.toFixed(2) + "
" +
"
$" + interestPayment.toFixed(2) + "
" +
"
$" + remainingBalance.toFixed(2) + "
" +
"
";
// For the last payment, ensure the remaining balance is exactly 0
if (i === numberOfPayments && remainingBalance > 0.01) { // Small tolerance for floating point errors
remainingBalance = 0;
}
}
tableHTML += "