The ConTec BML Viscometer 3 is designed to measure the rheological properties of fresh concrete. The measuring unit of this device is composed of two parts, where the rheological properties are only registered by the part least affected by end-effects. Thus it is assumed that the measured data is not influenced by end-effects, allowing for the use of an algebraically derived equation to convert the data to fundamental physical quantities. In this work, this important assumption is supported by numerical analysis. This has been done by comparing values calculated by numerical means, where end-effects are included in the analysis, with values calculated by analytical means, where end-effects are excluded. (C) 2008 Elsevier B.V. All rights reserved.