Success on Amazon hinges on a precise understanding of your numbers. Many sellers focus on "Top Line Revenue" without accounting for the complex fee structure of the Fulfillment by Amazon (FBA) program. This calculator helps you drill down into the real unit economics of your private label or wholesale business.
Key Metrics Explained
Selling Price: The list price your customer pays on Amazon.com.
Unit Cost: The total cost to manufacture or purchase one unit from your supplier.
FBA Fulfillment Fee: This covers the cost of picking, packing, and shipping your product to the customer, as well as customer service and returns.
Referral Fee: Amazon's "commission" for selling on their platform. For most categories, this is 15% of the total selling price.
ROI: Calculated as Net Profit divided by your initial Product Cost. A healthy FBA business typically targets over 100% ROI.
Real-World Example Calculation
Imagine you are selling a yoga mat for $35.00. Your manufacturing cost is $10.00 and it costs $2.00 to ship it from China to an Amazon warehouse. If the FBA fulfillment fee is $7.00 and the referral fee is 15% ($5.25), your total costs would be $24.25. Your net profit would be $10.75 per unit, resulting in a 30.7% profit margin and a 107.5% ROI.
Strategies to Improve FBA Margins
If your margins are slim (below 20%), consider optimizing your packaging to reduce the "Fulfillment Fee" tier, or negotiating lower unit costs with your supplier. Small changes in dimensions can often drop your product into a lower size tier, saving you dollars per unit instantly.
function calculateFBAProfit() {
var sellPrice = parseFloat(document.getElementById('sellingPrice').value);
var unitCost = parseFloat(document.getElementById('productCost').value);
var shipping = parseFloat(document.getElementById('shippingCost').value) || 0;
var fbaFee = parseFloat(document.getElementById('fbaFee').value) || 0;
var refPercent = parseFloat(document.getElementById('referralFeePercent').value) || 0;
var storage = parseFloat(document.getElementById('storageFee').value) || 0;
if (isNaN(sellPrice) || isNaN(unitCost)) {
alert("Please enter both Selling Price and Unit Cost.");
return;
}
// Calculations
var referralFeeValue = sellPrice * (refPercent / 100);
var totalExpenses = unitCost + shipping + fbaFee + referralFeeValue + storage;
var netProfit = sellPrice – totalExpenses;
var margin = (netProfit / sellPrice) * 100;
var roi = (netProfit / unitCost) * 100;
// Display Results
document.getElementById('fbaResults').style.display = 'block';
document.getElementById('resReferral').innerHTML = '$' + referralFeeValue.toFixed(2);
document.getElementById('resExpenses').innerHTML = '$' + totalExpenses.toFixed(2);
var profitEl = document.getElementById('resProfit');
profitEl.innerHTML = '$' + netProfit.toFixed(2);
profitEl.className = netProfit >= 0 ? 'result-value profit-positive' : 'result-value profit-negative';
document.getElementById('resMargin').innerHTML = margin.toFixed(2) + '%';
document.getElementById('resROI').innerHTML = roi.toFixed(2) + '%';
// Scroll to results on mobile
if (window.innerWidth < 600) {
document.getElementById('fbaResults').scrollIntoView({ behavior: 'smooth' });
}
}