Loan Payment Calculator (Mortgage Excel)
function calculateLoanPayment() {
let loanAmount = parseFloat(document.getElementById(‘loanAmount’).value);
let interestRate = parseFloat(document.getElementById(‘interestRate’).value) / 100 / 12;
let loanTerm = parseFloat(document.getElementById(‘loanTerm’).value) * 12;
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || loanAmount <= 0 || interestRate <= 0 || loanTerm <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
let monthlyPayment = (loanAmount * interestRate) / (1 – Math.pow(1 + interestRate, -loanTerm));
document.getElementById('payment').value = monthlyPayment.toFixed(2);
}
