Auto Loan Calculator with Extra Payments
Estimate your monthly payments, total interest paid, and time saved by making extra payments on your auto loan.
let autoLoanSteps = “”;
const currencySymbol = “$”, fixedCurrency = “USD”;
function calculateAutoLoan(){
autoLoanSteps=””;
const loanAmount = parseFloat(document.getElementById(“loanAmount”).value);
const interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100 / 12;
const loanTerm = parseFloat(document.getElementById(“loanTerm”).value) * 12;
const extraPayment = parseFloat(document.getElementById(“extraPayment”).value);
if(isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(extraPayment) || loanAmount <= 0 || loanTerm 0) {
const interestForMonth = currentBalance * interestRate;
const principalPayment = monthlyPayment – interestForMonth;
currentBalance -= principalPayment;
totalInterest += interestForMonth;
monthsPaid++;
if (currentBalance < 0) currentBalance = 0;
}
const totalLoanPaid = monthsPaid;
const loanTermSaved = loanTerm – totalLoanPaid;
document.getElementById("monthlyPayment").value = formatCurrency(monthlyPayment);
document.getElementById("totalInterest").value = formatCurrency(totalInterest);
document.getElementById("loanTermSaved").value = loanTermSaved;
autoLoanSteps += `
Inputs:Loan Amount: ${formatCurrency(loanAmount)}
Interest Rate: ${(interestRate * 12 * 100).toFixed(2)}%
Loan Term: ${loanTerm / 12} Years
Extra Payment: ${formatCurrency(extraPayment)}
`;
autoLoanSteps += `
Formulas:Monthly Payment = Loan Amount × (Interest Rate / (1 – (1 + Interest Ra
