The functionality of pigments and fillers is significantly affected by their state of dispersion at the point of application (e.g. in paints and varnishes). This state depends on the materials' original state of agglomeration and aggregation and on their processing, which typically aims at desagglomeration and partial disintegration by high shear stresses. In order to assess the dispersibility of pigments and fillers, a characterisation method is proposed, which comprises sample preparation by ultrasonic dispersion (USD) and particle size analysis by means of analytical centrifugation (AC). The characterisation method is tested within an interlaboratory comparison for four inorganic powders and involves different USD equipment and different AC techniques in different laboratories. The analyses delivered volume-weighted particle size distributions, which were statistically evaluated in order to assess the uncertainty of results within a laboratory and to quantify the variation among the different laboratories. Impacts of the material on the performance of the characterisation method are discussed as well as differences between the various AC techniques. (C) 2018 Elsevier B.V. All rights reserved.