function calculateFBA() {
var salePrice = parseFloat(document.getElementById('salePrice').value) || 0;
var productCost = parseFloat(document.getElementById('productCost').value) || 0;
var shipToAmazon = parseFloat(document.getElementById('shipToAmazon').value) || 0;
var referralFeePercent = parseFloat(document.getElementById('referralFeePercent').value) || 0;
var fulfillmentFee = parseFloat(document.getElementById('fulfillmentFee').value) || 0;
var storageFee = parseFloat(document.getElementById('storageFee').value) || 0;
var referralFeeAmount = salePrice * (referralFeePercent / 100);
var totalAmazonFees = referralFeeAmount + fulfillmentFee + storageFee;
var totalCostOfGoods = productCost + shipToAmazon;
var netProfit = salePrice – totalAmazonFees – totalCostOfGoods;
var profitMargin = (salePrice > 0) ? (netProfit / salePrice) * 100 : 0;
var roi = (totalCostOfGoods > 0) ? (netProfit / totalCostOfGoods) * 100 : 0;
document.getElementById('totalFeesDisplay').innerText = "$" + totalAmazonFees.toFixed(2);
document.getElementById('netProfitDisplay').innerText = "$" + netProfit.toFixed(2);
document.getElementById('marginDisplay').innerText = profitMargin.toFixed(2) + "%";
document.getElementById('roiDisplay').innerText = roi.toFixed(2) + "%";
if (netProfit < 0) {
document.getElementById('netProfitDisplay').style.color = "#d9534f";
} else {
document.getElementById('netProfitDisplay').style.color = "#1e7e34";
}
document.getElementById('results').style.display = 'block';
}
How to Calculate Amazon FBA Profit
Selling on Amazon using Fulfillment by Amazon (FBA) offers massive scale, but the fee structure can be complex. To accurately determine your bottom line, you must look beyond the simple difference between what you paid for an item and what it sold for.
Understanding the Key Components
Landed Product Cost: This is the price you pay the manufacturer per unit, including any taxes or packaging.
Referral Fee: Amazon's "commission" for selling on their platform. Most categories are charged 15%, but it varies from 8% to 45% depending on the niche.
FBA Fulfillment Fee: A per-unit fee that covers picking, packing, and shipping your product to the customer. This is based on the weight and dimensions of the item.
Monthly Storage Fees: Amazon charges for the space your inventory occupies in their warehouses. This cost increases significantly during Q4 (October–December).
Why Your Margin Matters
A healthy Amazon FBA business generally aims for a 30% profit margin. This provides a "buffer" for returns, PPC (Pay-Per-Click) advertising costs, and fluctuations in storage fees. If your margin is below 15%, you may struggle to remain profitable once advertising costs are factored in.
Realistic FBA Example
Imagine you are selling a yoga mat:
Sale Price: $40.00
Product Cost: $10.00
Shipping to Amazon: $2.00
Referral Fee (15%): $6.00
Fulfillment Fee: $7.50
Storage Fee: $0.50
In this scenario, your Total Fees are $14.00. Your Total Investment (Product + Shipping) is $12.00. Your Net Profit would be $14.00 per unit, resulting in a 35% Profit Margin and a 116% ROI. This represents a very healthy FBA product.