Chromatography is a tool to measure molecular interactions, and computational chemistry is a tool to explain molecular interactions. Therefore, reversed-phase liquid chromatography of acidic drugs using a pentyl- and an octyl-bonded silica gels was quantitatively analyzed in silico. A model pentyl- and an octyl-bonded silica gel and a methanol phases were constructed for docking with acidic drugs. Molecular interaction energy values based on van der Waals energy were obtained after docking an acidic drug into the model pentyl- or octyl-phases. Solvent effects, hydrogen bonding, and electrostatic energy values were obtained after docking an acidic drug onto the model methanol phase. Chromatographically measured log k values were correlated with the sum of van der Waals, hydrogen bonding, and electrostatic energy values. The correlation coefficient between the log k values measured using the pentyl-bonded silica gel phase and the molecular interaction energy values was 0.95 (n = 20); that between the log k values measured using the octyl-bonded silica gel and the molecular interaction energy values was 0.95 (n = 20).