フリマ計算, or "Flea Market Calculation," is a handy tool designed to calculate profits for online selling. The program offers two primary functions: "Sales Profit Calculation," which determines the profit amount after deducting fees from the selling price, and "Sales Price Calculation," which helps calculate the selling price needed to make a profit after including fees. Users simply select the price and shipping options, and the app automatically computes the results.

Compatible with various markets such as Mercari, Paypay Flea Market, Rakuma, and Yahoo Auctions, users can customize the display, hide certain information, and arrange items as needed. The app supports fixed shipping rates and provides additional features like registration, saving and loading capabilities, message templates for common transactions, and a memo function to save URLs and important keywords.