After water, concrete made from cement, water and aggregate is currently the most frequently used building material on our planet in terms of volume. The production of cement is associated with around 8% of anthropogenic greenhouse gas emissions. Limestone powder, which can be added to concrete in the concrete plant as an inert supplementary cementitious material, can significantly reduce the cement content in concrete. However, design and application rules have to be worked out that allow the production of a sufficiently high-performance and durable concrete. For this purpose, creditability factors (k-value) on the technically or normatively required w/c-ratio as well as the minimum cement content are suitable. Within the scope of the present work, with the aid of a comprehensive experimental program it was first shown that limestone powder does not significantly influence the reaction kinetics of the cement during hardening of the concrete. However, a noticeable contribution to the concrete performance is achieved mainly by physical effects. Hereby, at constant water content, high substitution rates lead to a significant decrease in concrete performance. By adjusting the absolute water content, comparable microstructure and performance of concretes with and without limestone powder can be achieved. As a result of a comprehensive literature study on the performance of concretes with limestone powder it can be stated that with a comparable compressive strength of the concrete also an equivalent, partly even better durability is achieved. In order to be able to predict the subsequent compressive strength even before the concrete is produced, the limestone powder should be taken into account in the determination of the necessary water-cement-ratio (w/c-ratio) as cement equivalent with the aid of a creditability factor. For this purpose, a precise method was presented that determines the creditability of the limestone powder as a function of the limestone powder content in the binder and of the specific surface areas of the limestone powder and the Portland cement used. For the practical mix design in compliance with the descriptive specifications for mix design according to DIN 1045-2, a simplification could be made, whereby a creditability factor of kKSM = 0.15 is proposed for limestone powder contents of up to 50 wt.-% on the binder. In addition, 100 % of the limestone powder can be credited to the cement content in order to comply with the minimum cement content according to DIN 1045-2, which, if implemented consistently, will lead to a significant reduction in cement-induced greenhouse gas emissions.