Concrete filled steel tubular (CFST) column is one of the most effective building structures types that combine high bearing capacity and economy. Three-dimensional nonlinear finite element analysis is the most common and reliable method for determining the bearing capacity of CFST columns. This approach is usually applied to individual elements and is not suitable for calculating buildings and structures with CFST elements as a single whole, due to high computational complexity. The purpose of the article is to develop a simplified model that allows reducing a three-dimensional problem of calculating a CFST column to a two-dimensional one. Rectangular CFST columns subjected to eccentric compression with eccentricity in two planes are considered. The problem dimension is reduced based on the hypothesis of plane sections. Rectangular elements are used for the concrete core and one-dimensional bar elements are used for the steel pipe. The developed model was verified by comparing calculation results with the results of three-dimensional finite element modeling in ANSYS. The maximum discrepancy between the results for stresses was 2.3 %. The model was also validated on experimental data for 38 samples presented in 3 different papers. The proposed model allows to significantly reduce the machine time costs when calculating CFST columns in a physically nonlinear formulation.