Ƙarin sunan fayil jerin haruffa ne a ƙarshen sunan fayil, wanda aka ware daga babban ɓangaren sunan ta ɗigo ko lokaci. Ana amfani da shi don nuna nau'in fayil ɗin da aikace-aikacen da za su iya buɗe ko sarrafa fayil ɗin. Misali, a cikin sunan fayil "report.docx," tsawo ".docx" yana nuna cewa fayil ɗin takaddun Microsoft Word ne.
