Monthly
Quarterly
Annually
function calculateAmortization() {
let loanAmount = parseFloat(document.getElementById(“loanAmount”).value);
let interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100;
let loanTerm = parseInt(document.getElementById(“loanTerm”).value);
let paymentFrequency = document.getElementById(“paymentFrequency”).value;
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || loanAmount <= 0 || interestRate <= 0 || loanTerm <= 0) {
alert("Please enter valid positive values for all fields.");
return;
}
let paymentsPerYear = paymentFrequency === "monthly" ? 12 : paymentFrequency === "quarterly" ? 4 : 1;
let numberOfPayments = loanTerm * paymentsPerYear;
let monthlyInterestRate = interestRate / paymentsPerYear;
let monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
let resultHTML = `
Amortization Schedule
| Payment # | Payment Amount | Principal Paid | Interest Paid | Remaining Balance |
|---|
`;
let remainingBalance = loanAmount;
for (let i = 1; i <= numberOfPayments; i++) {
let interestPaid = remainingBalance * monthlyInterestRate;
let principalPaid = monthlyPayment – interestPaid;
remainingBalance -= principalPaid;
resultHTML += `
| ${i} |
$${monthlyPayment.toFixed(2)} |
$${principalPaid.toFixed(2)} |
$${interestPaid.toFixed(2)} |
$${remainingBalance.toFixed(2)} |
`;
}
resultHTML += “
“;
document.getElementById(“amortizationResult”).innerHTML = resultHTML;
}
