The paper contributes to the global research of the best shape of cruciform samples for biaxial tensile tests. Based on literature research, one of the proposed samples’ shape comparison methodology was employed to achieve the ultimate results. A variety of specimens with different shapes were compared and modelled with the use of Finite Element Method (FEM). Afterwards, five the most promising sample shapes were examined on a tests stand to validate the simulation results. Based on the obtained research results a new parameter defining the ability of the cruciform sample to reach the possible achievable strain in the centre area, was introduced. The obtained data shows, that sample with the highest Relative Cost Function parameter (RCF) presented the highest strain in the gauge region and the sample with the lowest RCF reached the lowest strain in the center. The rest of the samples remained within the general trend showing a compatibility between the RCF parameter and the obtained strain.