Most of the components’ lifetime is consumed in the range of crack initiation and short crack growth. This paper shows the impact of notches in these early stages under creep-fatigue loading at high temperature. With the focus on round bar specimens having a circumferential notch the influence of different notch shapes, loading levels and conditions is assessed by a crack growth model. The crack tip loading is computed in form of a cyclic effective J-Integral considering the impact of (visco)plasticity induced crack closure based on finite element simulations. Based on this model, notch support factors for same local loading levels and crack depths are computed to quantify the notch support effect. The theoretical results are validated by experiments, where the short crack growth is measured. To give an idea of the applicability potential of the modelling approach, an industry relevant use case is presented.