The width and sprocket holes should be helpful, also super 8 comes (mostly) on reels that have a larger centre hole as compared to standard 8.

1932 marked the introduction year by Eastman Kodak of the revolutionary 8mm film gauge, known as Double Run 8mm or Double 8mm movie film (also as Double Regular 8mm, Regular 8mm, Standard 8mm or Normal 8mm). This film gauge was clearly based on its 16mm big brother, and had an additional sprocket hole added, with a frame size 1/4th that of 16mm film.

Eight millimetre also underwent a transformation in 1965. The frame image was enlarged by 50% by using smaller vertical perforations. The so called super 8 film was supplied in 50' 8mm cassettes.