Car Amortization Calculator (Extra Payment)
function calculateAmortization() {
const loanAmount = parseFloat(document.getElementById(“loanAmount”).value);
const interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100 / 12;
const loanTerm = parseInt(document.getElementById(“loanTerm”).value) * 12;
const extraPayment = parseFloat(document.getElementById(“extraPayment”).value);
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(extraPayment) || loanAmount <= 0 || interestRate <= 0 || loanTerm <= 0 || extraPayment 0) {
let interest = balance * interestRate;
let principal = monthlyPayment – interest;
balance -= principal;
totalInterest += interest;
months++;
if (balance < 0) balance = 0;
}
const totalPaid = loanAmount + totalInterest;
document.getElementById("monthlyPayment").textContent = monthlyPayment.toFixed(2);
document.getElementById("totalInterest").textContent = totalInterest.toFixed(2);
document.getElementById("loanTermLeft").textContent = months;
document.getElementById("totalPaid").textContent = totalPaid.toFixed(2);
}
