Accurately calculate your net profit, margins, and ROI after all Amazon fees.
Total Revenue:$0.00
Amazon Fees (Referral + FBA):$0.00
Total Product Costs:$0.00
Net Profit (Per Unit):$0.00
Profit Margin:0%
Return on Investment (ROI):0%
Understanding the Amazon FBA Profit Formula
Selling on Amazon via Fulfillment by Amazon (FBA) offers massive scale, but the fee structure can be complex. To understand your true bottom line, you must look beyond the gross sale price and subtract the "hidden" costs of doing business on the platform.
Key Metrics Explained
Referral Fee: This is essentially Amazon's commission for selling on their marketplace. For most categories, this is 15% of the total sale price.
FBA Fulfillment Fee: The cost for Amazon to pick, pack, and ship your product. This is based on the weight and dimensions of your item.
COGS (Cost of Goods Sold): This is what you paid your manufacturer for the product.
PPC Spend: Your marketing costs. To find the "per unit" advertising cost, take your total monthly ad spend and divide it by the number of units sold.
Example Calculation
Imagine you are selling a yoga mat for $40.00:
Product Cost: $10.00
Shipping to Amazon: $1.50
Referral Fee (15%): $6.00
FBA Fee: $7.50
PPC Ad Spend per unit: $3.00
Total Expenses: $28.00
Net Profit: $12.00
Profit Margin: 30%
ROI: 104% (Profit divided by your total investment of $11.50 for product and inbound shipping).
How to Increase Your FBA Margins
To maximize your Amazon business, focus on two levers: increasing price or decreasing costs. Many sellers overlook shipping costs or storage fees during Q4 (peak season), which can significantly eat into profits. Regularly auditing your FBA fees ensures Amazon hasn't mismeasured your product, placing it in a higher weight tier than necessary.
function calculateFBA() {
var salePrice = parseFloat(document.getElementById('salePrice').value) || 0;
var productCost = parseFloat(document.getElementById('productCost').value) || 0;
var shippingToAmz = parseFloat(document.getElementById('shippingToAmz').value) || 0;
var referralFeePct = parseFloat(document.getElementById('referralFee').value) || 0;
var fbaFulfillment = parseFloat(document.getElementById('fbaFulfillment').value) || 0;
var storageFee = parseFloat(document.getElementById('storageFee').value) || 0;
var ppcSpend = parseFloat(document.getElementById('ppcSpend').value) || 0;
var otherCosts = parseFloat(document.getElementById('otherCosts').value) || 0;
// Calculations
var amzReferralFee = salePrice * (referralFeePct / 100);
var totalAmzFees = amzReferralFee + fbaFulfillment + storageFee;
var totalOperatingCosts = productCost + shippingToAmz + ppcSpend + otherCosts;
var netProfit = salePrice – totalAmzFees – totalOperatingCosts;
var profitMargin = (salePrice > 0) ? (netProfit / salePrice) * 100 : 0;
var totalInvestment = productCost + shippingToAmz;
var roi = (totalInvestment > 0) ? (netProfit / totalInvestment) * 100 : 0;
// Display Results
document.getElementById('resRevenue').innerText = '$' + salePrice.toFixed(2);
document.getElementById('resFees').innerText = '$' + totalAmzFees.toFixed(2);
document.getElementById('resTotalCosts').innerText = '$' + totalOperatingCosts.toFixed(2);
var profitEl = document.getElementById('resNetProfit');
profitEl.innerText = '$' + netProfit.toFixed(2);
if (netProfit >= 0) {
profitEl.className = 'fba-result-value profit-positive';
} else {
profitEl.className = 'fba-result-value profit-negative';
}
document.getElementById('resMargin').innerText = profitMargin.toFixed(2) + '%';
document.getElementById('resROI').innerText = roi.toFixed(2) + '%';
document.getElementById('fbaResults').style.display = 'block';
}