From the theoretical atomic yields stress, the TMYS (Theoretical Macroscopic Yield Stress) for pure materials is obtained through the concept of EAS (Efficient Area of Stress) and fractal analysis. This analysis uses a universal USLM (Universal Scale Law of Measure) that obeys a Fractal Power Law which can be used at all scales (atomic, nano, micro, macro). The TMYS obtained depends only on a universal constant and on atomic distance which is the key factor for material characterization; this open new area of atomic reliable IQ (Insurance Quality) for macro characterization instead of expensive Destructive testing. The USLM gives also new theoretical relations for elastic limit of strain, toughness and fracture strength although more validations are necessary. The USLM is extended to non pure materials to take into account the microstructures (grain size, impurity, phases, solutions,...) and the temperature effects by introducing the concept of "efficient atomic distance". The TMYS is compared to theoretical and experimental results found in the present literature for numerous types of materials. The precision obtained by the USLM is the best. It is of an atomic order, with ratio of 0.99 for theoretical to experimental results, compared to other models which gives higher errors (10(2) to 10(4) Mpas). The generalization of the USLM to other physical measure is proposed to be used as a universal criterion which gives the scale-size effect.