A feature film is a film with a running time long enough to be considered the principal or sole film to fill a program. The notion of how long this should be has varied according to time and place. According to the Academy of Motion Picture Arts and Science, American Film Institute, and British Film institute, a feature film runs for 40 minutes or longer, while the Screen Actors Guild states that it is 80 minutes or longer.

 

So according to the Screen Actors Guild Star Wars The Force Awakens and Disny's Beauty and the Beast (animated) would be a feature film but the 1931 Dracula (the best) or The Nightmare Before Christmas are not a feature films.