The rapid growth in the human population and the frying methods in preparing food resulted in significant amounts of waste cooking oil (WCO) being generated globally. The excessive piling of the waste has become an alarming problem because the WCO disposal method is inefficient. People tend to dispose of WCO via irrigation systems by simply discarding it. Most WCO has been disposed of in sewage which has created various problems such as water pollution and soil pollution and has unfavorable consequences for the environmental system. From previous studies, it is reported that ginger can treat WCO. This research aims to investigate the effect of the surface area of ginger to treat WCO. For the methodology, the first step, the surface area of ginger (crushed and sliced) needs to be investigated. The ginger is crushed and sliced before WCO purification. The crushed and sliced ginger sample is then analysed using scanning electron microscopy (SEM) to examine the structure of ginger that affected WCO treatment. For the characterisation study of the purified WCO, the sample is studied using Fourier transform infrared spectroscopy (FTIR) to identify the functional group and composition present in the purified WCO. The SEM images of ginger before and after the WCO treatment show a significant difference, demonstrating that ginger has the potential to treat WCO. The highest percentage difference between WCO purified with sliced ginger is 3.33 % from alkane (CH2)n. In the WCO purified with crushed ginger, the glycerol group O-CH2 stretching band displayed the greatest percentage variation, at 2.22 %. In conclusion, the surface area of ginger plays an important role in WCO treatment. This research may be an essential requirement for WCO treatment before converting into other valuable products.