The Purpose of this study was to determine the best concentration of phosphoric acid (H3PO4) as an activator in making of activated charcoal from durian shell. This study used a completely randomized design (RAL) with 4 treatments and 4 replications which followed by Duncan’s New Multiple Range Test at level 5%. The treatments of this research were AA1 (concentration of H3PO4 5%), AA2 (concen…