Planaxis sulcatus is a medium-sized marine intertidal gastropod that occur throughout the Indo-Pacific Region (Houbrick 1987). The shell length of adult P. sulcatus ranges between 25 mm to 35 mm in length. In juveniles, average shell length upon settlement, ranges between 3 mm to 8 mm in length (Ohgaki 1997). Planaxis sulcatus achieve sexual maturity when they are approximately 1 year old with an average shell length of between 14 mm to 15 mm in length (Ohgaki 1997). P. sulcatus is known to exhibit some form of sexual dimorphism where female P. sulcatus are generally larger in size than their male counterparts (Ohgaki 1997). The proportions of females to males were observed to increases as size increases in populations of P. sulcatus (Ohgaki 1997).

The average size of a P. sulcatus on Heron Island is estimated to be approximately 24.8 mm in length based on a survey conducted on 200 random samples of P. sulcatus collected from a 600 m stretch beachrock, located on the Southside of Heron Island, on October 2011.