An estimate of the effective toughness of heterogeneous materials is proposed using the phase field fracture model and an FFT based homogenization framework. The estimate is based on the simulation of the fracture of a representative volume of the microstructure (RVE) controlled by a constant rate of energy dissipation [1]. The effective toughness corresponds to the total energy dissipated after the total fracture divided by the RVE cross-section [2]. The proposed estimate considers both the effect of the difference in toughness and stiffness of the phases. To improve toughness predictions, crack tip enrichment is used for modeling initial cracks. The method is applied to obtain the effective toughness of composites and elastic polycrystals in a series of examples. [1] P Aranda, J Segurado, Effective toughness estimation by FFT based phase field fracture: application to composites and polycrystals, Mechanics Research Communications 149, 104498, 2025 [2] P Aranda, J Segurado, A crack-length control technique for phase field fracture in FFT homogenization, International Journal of Numerical Methods in Engineering 126: e7664, 2025