Fixed Rate Mortgage Calculator (Math)
Use this calculator to determine your fixed-rate mortgage payments and total interest paid over time.
Monthly Payment: $0.00
Total Interest Paid: $0.00
Total Paid Over the Life of the Loan: $0.00
function calculateMortgage() {
const loanAmount = parseFloat(document.getElementById(“loanAmount”).value);
const interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100 / 12;
const 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 values for all fields.");
return;
}
const monthlyPayment = loanAmount * interestRate / (1 – Math.pow(1 + interestRate, -loanTerm));
const totalPaid = monthlyPayment * loanTerm;
const totalInterest = totalPaid – loanAmount;
document.getElementById("monthlyPayment").textContent = `$${monthlyPayment.toFixed(2)}`;
document.getElementById("totalInterest").textContent = `$${totalInterest.toFixed(2)}`;
document.getElementById("totalPaid").textContent = `$${totalPaid.toFixed(2)}`;
}
