Abstract For a comprehensive description of the steric structure of macromolecules, which includes molecular shape as well as coil density and flexibility, a novel analytical technique for aqueous systems is introduced. The reliability of the method is illustrated by investigations on narrowly distributed pullulan standards in the molar mass range from 10 5 to 10 6 g mol −1. Hydrodynamic information ( D, R D) was yielded by flow field-flow fractionation, while simultaneous scattering experiments delivered the corresponding ‘static’ dimension R G and molar mass M. The observed asymmetry-factor was R G R D = 1.7 . With increasing molar mass the mean coil density ρ Pol decreased from 19.1 to 2.6 mg ml −1 and the calculated persistence lengths l P increased, ranging from 1.4 to 3.1 nm. The results were found to be in good agreement with literature data and confirm the analytical potential of the applied technique.