The surface of 316L stainless steel can be coated with hydroxyapatite to overcome its disadvantages as a medical implant, such as low biocompatibility and the release of toxic metal ions in the body after implantation. The coating thickness is one of the important parameters in the coating process. The use of a model to predict the coating thickness is needed to achieve a standard thickness of the coating. This research aim is to determine the empirical model of the hydroxyapatite coating thickness on the surface of 316L stainless steel by the dip coating method. The HA slurry was made by mixing HA powder, polyethylene glycol, and distilled watere using a magnetic stirrer. The 316L stainless steel substrate were dipped into the slurry and then followed by a drying and sintering process. The empirical model of the HA coating thickness on the surface of the 316L stainless steel in this research is