SellerApp's FBA calculator for Amazon Sellers is a free Chrome extension that helps sellers analyze profits and determine if Fulfillment by Amazon (FBA) is the better choice for their products. By calculating the cost of goods sold, shipping fees, Amazon fees, and other variables, sellers can gain a clear understanding of their profit margins per unit. The extension also provides essential data such as net profit, net margin, and return on investment. With this information at hand, sellers can make informed decisions on product selection and whether to use FBA or Fulfillment by Merchant (FBM).