How our tools work
Each calculator runs entirely in your browser. Nothing you enter is sent to our server or stored. Seller calculators use the fee rules each platform publishes, and every seller tool page lists its official sources and the date we last checked them. Fees change from time to time and can depend on your country, account type and the promotions you use, so treat the results as careful estimates and confirm the final figures in your seller dashboard. Everyday tools show the formula they use and a worked example, so you can check any answer by hand.