The behavior of a structure under the effect of an earthquake is generally dependent on the mass and lateral stiffness of the structure. Apparently, the dynamic character of the structure will obviously not depend on just two parameters. However, due to the difficulty of calculating the period together with other factors, approximate methods have been given in the literature. The most widely accepted method of these is the first natural vibration period equation that is proposed by Rayleigh. In this paper period comparisons were made with 16 different period formulas of 9 different countries such as 1998, 2007 and 2018 Turkish Earthquake Code with an analytical study. In order to give explainable results of the comparison, a model frame type building without any irregularity was chosen. The story number for the selected model has been changed as 2-3-5-7-9-11. The frames were modeled in the ETABS program and period calculations were made according to the results that get from the program. In comparison, empirical period formulation in earthquake codes and Rayleigh method were used. According to the comparison made, the results obtained according to the Rayleigh formula up to 5 stories with the cracked section acceptance approach to the approximate period formula given in the regulation of 2018 at the ratio of 0.82-1.09, but the approximate formula gives higher results. However, if the cross-sections are thought to be cracked, the results obtained according to the Rayleigh formula show 1.16-1.62 times more results than the approximate method. After the 5 stories, the proportions changed into the ratios of 1.21-1.39 and 1.82-2.10 respectively.