The study that is being presented focused on the numerical analysis of the melting regime for various phase change materials (PCMs) in order to select an optimal material that would enhance the desalination efficiency of single-slope solar stills. While choosing the PCMs, the following factors were considered, availability, economic viability, environmental friendliness, and thermophysical properties. The study utilised ANSYS Fluent 18.1 to conduct a comparative analysis based on the melting of five different PCMs at different time stamps. The models and results showed that at 5000 s, Fe3O4 nanoparticle-enhanced PCM is the most effective of all the PCMs that were studied. This is because it melted completely before the other PCMs, which included RT35, Lauric Acid, CaCl2<middle dot>6H(2)O, and n-octadecane. The best inorganic PCM was discovered to be CaCl2<middle dot>6H(2)O, which had a maximum liquid fraction of around 68%. The best organic PCM was determined to be n-octadecane, which had a liquid fraction of nearly 57%. Lauric acid and RT35 achieved maximum liquid fractions of approximately 49% and 41%, respectively.