Numerical self-consistent field (SCF) lattice computations allow a priori determination of the equilibrium morphology and size of supramolecular structures originating from the self-assembly of neutral block copolymers in selective solvents. The self-assembly behavior of poly(ethylene oxide)-block-poly-epsilon-caprolactone (PEO-PCL) block copolymers in water was studied as a function of the block composition, resulting in equilibrium structure and size diagrams. Guided by the theoretical SCF predictions, PEO-PCL block copolymers of various compositions have been synthesized and assembled in water. The size and morphology of the resulting structures have been characterized by small-angle X-ray scattering, cryogenic transmission electron microscopy, and multiangle dynamic light scattering. The experimental results are consistent with the SCF computations. These findings show that SCF is applicable to build up roadmaps for amphiphilic polymers in solution, where control over size and shape are required, which is relevant, for instance, when designing spherical micelles for drug delivery systems (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 330-339