This document specifies a method of determining apparent viscosity of resins in a liquid state using a single cylinder type rotational viscometer. The method can be used for viscosity measurements in the range from 0,02 Pa Å" s 60 000 Pa Å" s. This document is applicable to both, Newtonian and non-Newtonian liquids and the measured apparent viscosity depends on the velocity gradient to which the liquids are subjected during the measurement.