This paper presents a simplified third-generation wind-wave model called METUS3. The model incorporates all third-generation model properties. It accounts for wave energy input from wind. nonlinear energy transfer due to wave-wave interactions, and energy dissipation due to wave breaking and bottom friction. Furthermore, it includes an efficient and simple representation of wave propagation. The model is applicable to water bodies of unlimited water depths of constant finite water depths without any adjustment. Several applications of METUS3 are presented, including one storm over the Sea of Marmara and three other storms over the Adriatic Sea. The model predictions show good agreement with observations and predictions of the more complicated third generation models such as METU3 or WAM. In its present version, the model assumes constant wind properties along characteristics covering the fetch area, which may be a limitation for extremely nonhomogeneous wind fields over very large water bodies. METUS3 can be used efficiently for standard engineering applications on personal computers.