(Received 15 July 2021;; accepted 30 August 2021) In this study, numerical modal analyses are conducted on steel plates supported with various numbers of transverse beams. Natural frequency and mode shapes are obtained for each model. The same analyses are also repeated for plates with various thicknesses. Finally, the correlation between the number of supporting beams and natural frequencies is examined. The change in natural frequencies with respect to plate thickness is emphasized. In addition, general surface regression formulas of flexural natural frequencies with respect to the number of supporting beams and plate thicknesses are obtained.