Amortization Table
| Payment Number |
Payment ($) |
Principal ($) |
Interest ($) |
Balance ($) |
function calculateMortgage() {
const loanAmount = parseFloat(document.getElementById(‘loanAmount’).value);
const interestRate = parseFloat(document.getElementById(‘interestRate’).value) / 100 / 12;
const loanTerm = parseInt(document.getElementById(‘loanTerm’).value) * 12;
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || loanAmount <= 0 || interestRate <= 0 || loanTerm <= 0) {
alert("Please enter valid positive values for all fields.");
return;
}
const monthlyPayment = (loanAmount * interestRate) / (1 – Math.pow(1 + interestRate, -loanTerm));
const totalAmountPaid = monthlyPayment * loanTerm;
const totalInterest = totalAmountPaid – loanAmount;
document.getElementById('monthlyPayment').value = monthlyPayment.toFixed(2);
document.getElementById('totalInterest').value = totalInterest.toFixed(2);
document.getElementById('totalAmountPaid').value = totalAmountPaid.toFixed(2);
generateAmortizationTable(loanAmount, interestRate, loanTerm, monthlyPayment);
}
function resetCalculator() {
document.getElementById('mortgage-calculator-form').reset();
document.getElementById('monthlyPayment').value = '';
document.getElementById('totalInterest').value = '';
document.getElementById('totalAmountPaid').value = '';
document.getElementById('amortizationTableContent').innerHTML = '';
}
function generateAmortizationTable(loanAmount, interestRate, loanTerm, monthlyPayment) {
let balance = loanAmount;
const amortizationTable = document.getElementById('amortizationTableContent');
amortizationTable.innerHTML = ''; // Clear existing table content
for (let i = 1; i <= loanTerm; i++) {
const interestPayment = balance * interestRate;
const principalPayment = monthlyPayment – interestPayment;
balance -= principalPayment;
const row = amortizationTable.insertRow();
row.insertCell(0).innerText = i;
row.insertCell(1).innerText = monthlyPayment.toFixed(2);
row.insertCell(2).innerText = principalPayment.toFixed(2);
row.insertCell(3).innerText = interestPayment.toFixed(2);
row.insertCell(4).innerText = Math.max(balance, 0).toFixed(2); // Prevent negative balance
}
}
