Abstract: A new general dimensionless design diagram is developed mainly for the calculation of reinforced concrete beams. The traditional “equivalent rectangular stress block” is not used in the method. The diagram can be used for different steel strength and concrete strength classes from C15 to C50. Instead of only one ultimate strain of concrete the whole stress-strain relationship of concrete given in “concrete structural design code” can be taken into account. The calculation is simple and a check of the depth of compressive zone is not necessary. It can be used for the design of members under flexural and axial loads. Many useful results are available, such as internal Lever arm ratio, extreme fiber strains of concrete, steel strains, and the ratio of neutral axis depth. They are illustrative and clear. A new and more accurate method for the design of concrete members is provided.