Loan Amortization Calculator Excel

let amortizationSteps = “”; const currencySymbol = “$”, fixedCurrency = “USD”; function calculateAmortization(){ amortizationSteps=””; 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)); document.getElementById("monthlyPayment").value = formatCurrency(monthlyPayment); amortizationSteps += `Inputs:
Loan Amount: ${formatCurrency(loanAmount)}
Interest Rate: ${(interestRate * 12 * 100).toFixed(2)}%
Loan Term: ${loanTerm / 12} years

`; amortizationSteps += `Formulas:
Monthly Payment = Loan Amount × Interest Rate / (1 – (1 + Interest Rate) ^ -Loan Term)

`; amortizationSteps += `Results:
Monthly Payment: ${formatCurrency(monthlyPayment)}
`; amortizationSteps += `Tip: The longer the term, the lower the monthly payment, but the more you will pay in interest over the life of the loan.`; if (document.getElementById(“calculationStepsAmortization”).style.display === “block”) { document.getElementById(“calculationStepsAmortization”).innerHTML = amortizationSteps; } } function resetAmortization() { document.querySelectorAll(“#calculator input”).forEach(el => el.value = “”); amortizationSteps = “”; document.getElementById(“calculationStepsAmortization”).innerHTML = “

Not calculated yet.

“; } function toggleAmortizationSteps() { const s = document.getElementById(“calculationStepsAmortization”); const a = document.getElementById(“toggleArrowAmortization”); if (s.style.display === “none” || s.style.display === “”) { s.style.display = “block”; a.style.transform = “rotate(180deg)”; s.innerHTML = amortizationSteps || “

Not calculated yet.

“; } else { s.style.display = “none”; a.style.transform = “rotate(0deg)”; } } function formatCurrency(n) { return currencySymbol + n.toFixed(2) + ” ” + fixedCurrency; }