Nonlinear fracture process zone is associated with various material failure mechanisms, and thus its size estimation is of fundamental issues in understanding material failure behaviors. Then, the size of the fracture process zone is computationally estimated by utilizing a cohesive zone modeling approach. Geometrically similar single edge notched bending and compact tension configurations are employed with various combinations of the fracture energy, cohesive strength and elastic modulus, which lead to 91 cases. The computational results demonstrate the consistency and convergence of the fracture process zone size according to the change of the material properties and the increase of structural sizes. Additionally, the fracture process zone size is nondimensionalized through using a characteristic length. The nondimensionalized results illustrate the independence of material properties and structural geometries according to the increase of structural sizes. Therefore, the fracture process zone size in the cohesive zone model can be considered as an intrinsic material property.