Abstract An efficient approach to predicting the welding angular distortion of large structures by using scalar input variables with no restriction on the mesh size near the welding region is proposed. To transform the input variables according to the mesh size, the explicit form of the force matrix is derived based on finite element theory. The proposed method is easily applied and requires only the measured distortion rate of a unit welded specimen and a user-designed mesh system to conduct the welding distortion analysis. The proposed method was applied to various case studies for verification, and the results show that the proposed method can effectively predict the welding angular distortion.