Purpose. The purpose of the scientific article is to study and substantiate the principle methodology for calculating the bearing capacity of a screw pile with a spiral blade on the basis of field tests of a prototype pile using existing methods of theoretical calculation of similar piles. Determination of the bearing capacity of a pile with a spiral blade by the soil according to the first limit state. Also, the goal is to determine certain regularities in the modeling of pile structure. Methodology. A metal elements pile is used as a test sample. Determination of the theoretical bearing capacity of the pile in the vertical direction is conducted using formulas and calculation data from Appendix H.5 (DBN B.2.1-10-2009, 2011). The basic solution is that the load-bearing capacity of the pile is achieved due to the adhesion of each individual blade to the soil, which in total reflects the final value of the load-bearing capacity of the pile. Findings. Six experimental piles were installed and tested with static axial compressive and pullout loads. The estimated compressive, pullout and horizontal loads allowed for test piles, turned in to the design mark and tested without soaking subsoils, were determined. In this work, on the basis of experiments, the possibility of using the calculation data existing in the regulatory documentation as a justified theoretical calculation of pile-based foundations in the design of buildings and structures in general with the use of piles with a spiral blade is proven. Originality. A refined mathematical dependence for determining the bearing capacity of a screw pile with a spiral blade by the soil is proposed and the possibility of its use is confirmed experimentally. Practical value. The proposed method makes it possible to substantiate and use screw piles with a spiral blade for pile foundations.