There are 80 calories in a Snickers Fun Size bar, as stated on the Snickers website. The nutritional information reported by the website is listed with a serving size of two bars as having 160 calories total, or 80 calories each.
Fun Size Snickers bars are each approximately 17 grams in weight and are sold in varying quantities and package sizes. Of the 160 calories contained in the serving size of two Snickers Fun Size bars, the Snickers website reports that 70 calories are from fat. Thus, each Snickers Fun Size bar contains 80 calories, with 35 calories from fat.