The average length of an ant is about 5mm. Most of the ants that are found have a length between 5mm to 15 mm. Exceptional are definitely present, like some ants can be as small as 1mm to 2 mm while some can be as big as 30mm. So variations among this species are definitely there, but average size of ants that are found range between 5mm to 15mm. All the ants that are present have three distinct body parts like the head, abdomen and thorax.