<p>In exceptional cases required by design conditions, the need for dimensional manipulation by changing the length of one or more links of a four-bar mechanism may pose a particular problem. In this case, other dimensions of the mechanism links that have not been dimensional manipulated must be found by dimensional synthesis. After dimensional synthesis, the main goal is to get minimum deviation errors according to precision points before dimensional manipulation. This work presents a solution method using nonlinear regression analysis for the dimensional synthesis of the four-bar mechanism. Dimensional manipulation was performed by shortening the crank link of a four-bar mechanism by 10 % to apply the solution method. The solution was applied according to 11 precision points, and maximum deviation errors of the precision points were obtained as ΔDx = 0.1029 and ΔDy = 0.1064. After the calibration of the Ay parameter, the deviation error was obtained as ΔDy = −1.5464. This method again applied according to 11 sensitive points, and dimensional synthesis of the four-bar mechanism was made before manipulation. It aimed to compare the results with the dimensional manipulation results and to determine the method’s sensitivity. The new coupler curve has been obtained with relatively minor deviations according to the precision points. The maximum deviations were obtained as ΔDx = −0.00001387 and ΔDy = 0.09739. A similar study covering the presented solution approach was not found in the literature. For this reason, the solution approach has not compared with the results of dimensional synthesis studies conducted in quite different numbers.</p>