Reels of 8mm film, Super 8mm and 16mm film each have different lengths and run at different frame rates. So, the answers depends on the diameter of the reel and the type of film. 8mm and Super 8mm typically are shown at 18 frames per second. 16mm film is typically shown at 24 frames per second. Here is a table which shows the lengths and times depending on the size of the reel and the type of film.