Use this calculator to estimate the cost and savings of transferring your credit card balance to a new card with a promotional balance transfer offer. This can be a great way to save money on interest if you have a significant balance and can pay it off before the promotional period ends.
function calculateBalanceTransfer() {
var currentBalance = parseFloat(document.getElementById("currentBalance").value);
var currentInterestRate = parseFloat(document.getElementById("currentInterestRate").value) / 100;
var transferFeePercentage = parseFloat(document.getElementById("transferFee").value) / 100;
var promoApr = parseFloat(document.getElementById("promoApr").value) / 100;
var promoPeriodMonths = parseInt(document.getElementById("promoPeriodMonths").value);
var regularApr = parseFloat(document.getElementById("regularApr").value) / 100;
var payoffTimeMonths = parseInt(document.getElementById("payoffTimeMonths").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(currentBalance) || isNaN(currentInterestRate) || isNaN(transferFeePercentage) || isNaN(promoApr) || isNaN(promoPeriodMonths) || isNaN(regularApr) || isNaN(payoffTimeMonths) ||
currentBalance <= 0 || currentInterestRate < 0 || transferFeePercentage < 0 || promoApr < 0 || promoPeriodMonths <= 0 || regularApr < 0 || payoffTimeMonths <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// — Calculations —
// 1. Cost of transfer
var transferFeeAmount = currentBalance * transferFeePercentage;
// 2. Interest paid if NOT transferring (simplified for target payoff time)
// This is an approximation, assumes fixed payments that would pay off the balance in targetTimeMonths
// A more accurate calculation would involve an amortization schedule.
var monthlyPaymentToPayOff = currentBalance / payoffTimeMonths; // Simplified payment amount
var interestPaidWithoutTransfer = 0;
var remainingBalanceWithoutTransfer = currentBalance;
var monthlyRateCurrent = currentInterestRate / 12;
for (var i = 0; i < payoffTimeMonths; i++) {
var interestThisMonth = remainingBalanceWithoutTransfer * monthlyRateCurrent;
interestPaidWithoutTransfer += interestThisMonth;
remainingBalanceWithoutTransfer -= (monthlyPaymentToPayOff – interestThisMonth);
if (remainingBalanceWithoutTransfer 0 && currentInterestRate > 0) {
// A more robust calculation might be needed here for very short payoff times.
// For simplicity, we'll use the calculated interest.
} else {
interestPaidWithoutTransfer = 0; // No interest if rate is 0 or payoff time is 0
}
// 3. Interest paid WITH balance transfer
var interestPaidWithTransfer = 0;
var remainingBalanceWithTransfer = currentBalance;
var monthlyRatePromo = promoApr / 12;
var monthlyRateRegular = regularApr / 12;
// Interest during promo period
for (var i = 0; i < promoPeriodMonths; i++) {
if (remainingBalanceWithTransfer <= 0) break;
var interestThisMonth = remainingBalanceWithTransfer * monthlyRatePromo;
interestPaidWithTransfer += interestThisMonth;
// Assume a minimum payment that covers interest + a small principal payment for this calculation
// or for simplicity, assume we are paying towards the target payoff time.
// Let's assume we're still aiming for the original payoff time for consistent comparison.
var estimatedPayment = currentBalance / payoffTimeMonths;
var principalPayment = estimatedPayment – interestThisMonth;
if (principalPayment < 0) principalPayment = 0; // Ensure we don't add negative principal
remainingBalanceWithTransfer -= principalPayment;
}
// Interest after promo period until payoff
for (var i = promoPeriodMonths; i < payoffTimeMonths; i++) {
if (remainingBalanceWithTransfer <= 0) break;
var interestThisMonth = remainingBalanceWithTransfer * monthlyRateRegular;
interestPaidWithTransfer += interestThisMonth;
var estimatedPayment = currentBalance / payoffTimeMonths;
var principalPayment = estimatedPayment – interestThisMonth;
if (principalPayment < 0) principalPayment = 0;
remainingBalanceWithTransfer -= principalPayment;
}
// If after promo period and regular APR, the balance isn't paid off by target payoff time,
// we need to calculate the total interest to pay off remaining balance.
// This is a more complex scenario. For this calculator, we will cap the interest calculation
// at the `payoffTimeMonths` and assume the `estimatedPayment` is sufficient.
// If `remainingBalanceWithTransfer` is still positive after `payoffTimeMonths` with this simplified payment,
// it indicates the target payoff time might be too aggressive with the given rates.
var totalCostWithTransfer = transferFeeAmount + interestPaidWithTransfer;
var totalPaidWithoutTransfer = currentBalance + interestPaidWithoutTransfer;
var totalPaidWithTransfer = currentBalance + transferFeeAmount + interestPaidWithTransfer;
var savings = interestPaidWithoutTransfer – (transferFeeAmount + interestPaidWithTransfer);
var htmlOutput = "