Lower Loan Interest Rates Calculator

let calculationSteps = “”; const currencySymbol = “$”, fixedCurrency = “USD”; function calculateLoan(){ calculationSteps=””; const loanAmount = parseFloat(document.getElementById(“loanAmount”).value); const interestRate = parseFloat(document.getElementById(“interestRate”).value) / 100; const newInterestRate = parseFloat(document.getElementById(“newInterestRate”).value) / 100; const loanTerm = parseInt(document.getElementById(“loanTerm”).value); if(isNaN(loanAmount) || isNaN(interestRate) || isNaN(newInterestRate) || isNaN(loanTerm) || loanAmount <= 0 || loanTerm <= 0){ alert("Please enter valid positive values for all fields."); return; } const monthlyPaymentCurrent = (loanAmount * interestRate) / (1 – Math.pow(1 + interestRate, -loanTerm * 12)); const totalCostCurrent = monthlyPaymentCurrent * 12 * loanTerm; const monthlyPaymentNew = (loanAmount * newInterestRate) / (1 – Math.pow(1 + newInterestRate, -loanTerm * 12)); const totalCostNew = monthlyPaymentNew * 12 * loanTerm; document.getElementById("monthlyPayment").value = formatCurrency(monthlyPaymentNew); document.getElementById("totalCost").value = formatCurrency(totalCostNew); calculationSteps += `Inputs:
Loan Amount: ${formatCurrency(loanAmount)}
Current Rate: ${(interestRate * 100).toFixed(1)}%
New Rate: ${(newInterestRate * 100).toFixed(1)}%
Loan Term: ${loanTerm} years

`; calculationSteps += `Formulas:
Monthly Payment = Loan Amount × Rate / (1 – (1 + Rate)^(-Term))
Total Cost = Monthly Payment × 12 × Term

`; calculationSteps += `Results:
Monthly Payment (New Rate): ${formatCurrency(monthlyPaymentNew)}
Total Loan Cost (New Rate): ${formatCurrency(totalCostNew)}
`; if(document.getElementById(“calculationSteps”).style.display === “block”){ document.getElementById(“calculationSteps”).innerHTML = calculationSteps; } } function resetLoan(){ document.querySelectorAll(“#loan-interest-calculator-form input”).forEach(el => el.value = “”); calculationSteps = “”; document.getElementById(“calculationSteps”).innerHTML = “

Not calculated yet.

“; } function toggleCalculationSteps(){ const s = document.getElementById(“calculationSteps”); const a = document.getElementById(“toggleArrow”); if(s.style.display === “none” || s.style.display === “”){ s.style.display = “block”; a.style.transform = “rotate(180deg)”; s.innerHTML = calculationSteps || “

Not calculated yet.

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