In this paper the sensitivity of the configuration of a mechanism to small variations in the precision point locations and corresponding coupler rotations is presented. The changes in the locations of the centerpoints and circlepoints, hence the dyads constituting the mechanism, due to these variations are determined by evaluating the total differentials of these quantities. The method is applied to mechanisms designed by the Burmester Theory of Planar Motion for four precision and five precision points. This additional information on sensitivity is shown to be useful in the process of mechanism design (Mahableshwarkar, 1989). Numerical examples are included to illustrate the formulation.