A method previously proposed for calculating the radius of gyration and the intrinsic viscosity of dendrimers is modified to give a more accurate description of existing experimental data. The new method includes some features that were not previously considered, namely: (a) a correction term to take into account the contribution of individual friction beads, whose volumes are not negligible in comparison with the molecule size, (b) a realistic distribution of internal angles between successive beads that define branching points in the molecule, (c) a distribution of distances between branching points computed from molecular dynamics simulations of a small dendrimer with explicit solvent. Modification (a) alone is able to give a good description of the experimental results obtained for polypropylene-imide with a diaminobutane core in water, while the simultaneous use of the three modifications is needed to adequately describe the experimental data of monodendrons and tridendrons of polybenzylether in THF. (c) 2007 Elsevier Ltd. All rights reserved.