The goal of the research is to improve the assessing system of physical fitness of military personnel. Methods: theoretical analysis and generalization; interpolation; method of least squares; regression analysis. Material: the ratings of the 4-point assessment of servicemen and service women readiness of the Armed Forces of Ukraine were obtained according to the requirements of the 100-point ECTS scale. Linear and non-linear regression equations were used to determine the accuracy of scoring for quantitative and qualitative indicators of the body weight of women and men of different height, age and body constitution. Results. It was established that the 4-point assessment of body weight of soldiers according to the rating requirements from ‘excellent, A’ level to ‘unsatisfactory, F’ level determines the quality of the nonlinear regression equation, which is inferior to the maximum possible selection (D = 94.57%) and has accuracy, which is lower than the high one (Ā = 6.88%). Also, the number of calculated points for servicemen and servicewomen body weight was calculated with the most successful selection of the nonlinear regression equation (D = 100%) and its maximum accuracy (Ā = 0%). Conclusions. The proposed method made it possible to obtain the levels of preparedness, to determine their accuracy according to the 4-point assessment of the body weight of women and men, and to achieve the equivalence of its qualitative and quantitative indicators with respect to the requirements of the 100-point rating scale.