Loan Calculator for Car with Extra Payments
Total Loan Payment: $0.00
Loan Paid Off In: 0 Years
Total Interest Paid: $0.00
function calculateLoan() {
let loanAmount = parseFloat(document.getElementById(“loanAmount”).value);
let interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100 / 12;
let loanTerm = parseInt(document.getElementById(“loanTerm”).value) * 12;
let extraPayment = parseFloat(document.getElementById(“extraPayment”).value);
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(extraPayment)) {
alert(“Please fill in all fields with valid numbers.”);
return;
}
let monthlyPayment = loanAmount * interestRate / (1 – Math.pow(1 + interestRate, -loanTerm));
let totalPayment = 0;
let totalInterest = 0;
let months = 0;
while (loanAmount > 0) {
let interest = loanAmount * interestRate;
let principal = monthlyPayment – interest + extraPayment;
loanAmount -= principal;
totalPayment += monthlyPayment + extraPayment;
totalInterest += interest;
months++;
if (loanAmount < 0) break;
}
let yearsRemaining = (months / 12).toFixed(2);
document.getElementById("totalPayment").innerText = "$" + totalPayment.toFixed(2);
document.getElementById("loanTermRemaining").innerText = yearsRemaining;
document.getElementById("totalInterestPaid").innerText = "$" + totalInterest.toFixed(2);
}
