In a previous study it was found that dynamic modulus (E) obtained from Impulse Load Test (ILT) is lower than dynamic modulus obtained from Ultrasonic Pulse Velocity Test (UPVT), which is theoretically not correct. In order to investigate this problem, the theoretical aspects involved in E-Calculations were checked by calculating the lateral strain involved in UPVT. Two finite element software programs (Marc and Patran) were selected for this purpose. In addition the effect of diameter on lateral strains of 12 inch length concrete samples was also investigated.