The Amazon FBA Calculator is a free tool designed to help sellers accurately assess the costs associated with using Amazon's Fulfillment by Amazon (FBA) service. It allows users to calculate various expenses, including product costs, shipping fees, Amazon fees, and marketing costs, ensuring a comprehensive understanding of profitability. By providing insights into net profit and profit margins, the calculator aids sellers in making informed decisions about product selection and pricing strategies, ultimately enhancing their success in the competitive e-commerce landscape.