This document specifies the measurement of setting time of a prepared cementitious or calcium sulfate-based floor levelling compound, after mixing with the liquid component, e.g. water. This document applies to cementitious and calcium sulfate-based floor levelling compounds used for the preparation of subfloors to ensure the suitability of the substrate prior to the installation of floor coverings. By using the floor levelling compound, a homogeneous layer is built up on the load-bearing substrate, to ensure consistent absorbency, evenness and strength.