This paper presents a mixture design method using the cementitious material for the design of concrete mixtures to assess early age strength and self-compactability. The proposed method adopted strength based mixture design method in addition to the packing theory to achieve target strength; enhanced durability and minimum paste volume. Packing theory was adopted to determine the aggregate proportions, binder paste is then filled in voids between aggregates to tightly pack concrete. The factors that influence the strength and durability of concrete are the amount of supplementary cementitious material (SCM), cement, and water. Compressive strength and water to cementitious material relationship were introduced depending on data from previous literature on concrete. Water to cementitious material ratio is used in place of water to cement ratio, early strength could be achieved in SCMs concrete. The optimal percentage of SCM for use in concrete was assessed using strength efficiency method. Using the proposed mixture design method, it was found that self-compacting concrete (SCC) made with an optimal percentage of metakaolin as SCM achieved the expected strengths of 60, 90 and 120 MPa at 28 days of curing.