A quick, easy and novel method to determine pore volume of porous copolymer beads on the basis of their density (d) in dry state is developed. The only apparatus required is a 10-ml measuring cylinder. The equations to calculate pore volumes are: 11.993d(2) - 14.03d + 4.2 for styrene-divinylbenzene; 13.221d2 - 15.654d + 4.7223 for 4-vinylpyridine-divinylbenzene, 5.2348d(2) - 8.0647d + 3.1612 for glycidylmethacrylate-ethyleneglycoldimethacrylate, 11.365d(2) - 12.925d + 3.7972 for 4-vinylpyridine-ethyleneglycoldimethacrylate and 5.7388d(2) - 7.6575d + 2.6864 for N-vinylcarbazole-divinylbenzene. An ideally close match of pore volume calculated by these equations and the pore volume measured by mercury porosimetry is achieved. (C) 2002 Elsevier Science B.V. All rights reserved.