function calculateExchange() {
var newPrice = parseFloat(document.getElementById('newPrice').value);
var tradeValue = parseFloat(document.getElementById('tradeValue').value) || 0;
var promoAmount = parseFloat(document.getElementById('promoAmount').value) || 0;
var taxRate = parseFloat(document.getElementById('taxRate').value) || 0;
if (isNaN(newPrice) || newPrice <= 0) {
alert('Please enter a valid price for the new iPhone.');
return;
}
// Calculation Logic
// In most regions, tax is calculated on the net price after trade-in,
// but for safety we calculate subtotal first.
var discountedPrice = newPrice – tradeValue – promoAmount;
if (discountedPrice < 0) discountedPrice = 0;
var taxAmount = discountedPrice * (taxRate / 100);
var finalTotal = discountedPrice + taxAmount;
var monthly = finalTotal / 24;
// Display Results
document.getElementById('totalCost').innerText = '$' + finalTotal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('subtotalDisplay').innerText = '$' + discountedPrice.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('taxDisplay').innerText = '$' + taxAmount.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('monthlyDisplay').innerText = '$' + monthly.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) + '/mo';
document.getElementById('resultArea').style.display = 'block';
}
How to Use the iPhone Exchange Rate Calculator
Upgrading to the latest iPhone often involves trading in your current device to offset the cost. This iPhone exchange rate calculator helps you determine the "real-world" cost of your next purchase by factoring in trade-in values, carrier promotions, and local sales tax.
Key Factors Influencing Your Upgrade Cost
Retail Price: The MSRP of the new iPhone model (e.g., iPhone 15, iPhone 15 Pro Max).
Trade-in Value: The amount Apple or a third-party buyer offers for your old device. This depends on the model, storage capacity, and condition.
Carrier Promotions: Many carriers offer bill credits (e.g., $800 off over 36 months) when you trade in an eligible device.
Sales Tax: While trade-ins often reduce the taxable amount in some states, others tax the full retail price before discounts.
iPhone Upgrade Example
Suppose you are buying a new iPhone 15 Pro for $999. You trade in an iPhone 13 Pro valued at $400. Your local tax rate is 8%.
To get the best exchange rate for your iPhone, ensure your device is in good condition. Use a case and screen protector to prevent scratches, as "Mint Condition" devices fetch significantly higher trade-in prices. Additionally, unlocking your phone from your carrier before selling it to a third party can increase its market value by 10-20%.