Membrane filtration is widely used in water treatment, biopharmaceutical manufacturing, and industrial processes, where particle retention is critical for product quality and safety. The micron rating of a membrane is a primary indicator of its filtration capability, yet the actual particle retention performance may vary significantly depending on membrane material, pore distribution, and operational conditions. This study investigates the correlation between membrane micron rating and particle retention efficiency across different membrane types, including polypropylene (PP), polyethersulfone (PES), and polyvinylidene fluoride (PVDF). Standardized particle challenge tests were conducted using polystyrene latex (PSL) beads ranging from 0.1 μm to 10 μm under controlled pressure and flow conditions. The results demonstrate a strong inverse correlation between membrane micron rating and particle retention efficiency, with material-dependent variations. These findings provide a practical reference for selecting membranes for specific filtration applications and optimizing filtration performance. This article is also available at: Econe Filtration