First Time Home Loan Calculator (NZ)
Use this tool to estimate your home loan eligibility and payments based on your income and other factors.
Calculation Steps
1. Calculate monthly interest rate.
2. Apply loan amortization formula to calculate monthly payment.
function calculateHomeLoan() {
const income = parseFloat(document.getElementById(‘income’).value);
const loanAmount = parseFloat(document.getElementById(‘loan-amount’).value);
const loanTerm = parseInt(document.getElementById(‘loan-term’).value);
const interestRate = parseFloat(document.getElementById(‘interest-rate’).value) / 100 / 12;
const deposit = parseFloat(document.getElementById(‘deposit’).value);
if (isNaN(income) || isNaN(loanAmount) || isNaN(loanTerm) || isNaN(interestRate) || isNaN(deposit)) {
alert(“Please fill out all fields correctly.”);
return;
}
const loanAmountAfterDeposit = loanAmount – deposit;
const monthlyPayment = (loanAmountAfterDeposit * interestRate) / (1 – Math.pow(1 + interestRate, -loanTerm * 12));
document.getElementById(‘monthly-payment’).value = monthlyPayment.toFixed(2);
document.getElementById(‘loan-calculation-steps’).style.display = “block”;
}
