Herein, we fabricate hollow silica nanoparticles with exceptionally narrow sizedistributions that inherently possess two distinct length scales—tens of nanometerswith regards to the shell thickness, and hundreds of nanometers in regards to thetotal diameter. We characterize these structures using dynamic and static lightscattering (DLS and SLS), small angle X-ray scattering (SAXS), and transmissionelectron microscopy (TEM), and we demonstrate quantitative agreement amongall methods. The ratio between the radius of gyration (SLS) and hydrodynamicradius (DLS) in these particles equals almost unity, corresponding to ideal capsulebehavior. We are able to resolve up to 20 diffraction orders of the hollow sphereform factor in SAXS, indicating a narrow size distribution. Data from light andX-ray scattering can be combined to a master curve covering a q-range of fourorders of magnitude assessing all hierarchical length scales of the form factor.The measured SLS intensity profiles noticeably change when the scatteringcontrast between the interior and exterior is altered, whereas the SAXS intensityprofiles do not show any significant change. Tight control of the aforementionedlength scales in one simple and robust colloidal building block renders theseparticles suitable as future calibration standards.