Ok humans have a colon, and a small intestine, which differ in both size and width. The Colon, better known as the large intestine is shorter yet wider in size with an average of about 5-6ft. The small intestines, is thinner yet longer in size than that of the colon, with an average of 20-22ft long in the average adult, however this trait can differ with size. Hope this helped =] best wishes! Length Of Human Intestines. Length Of Large Intestine. The average length of the small intestine is 22 feet. The average length of the large intestine is 5 feet.