This paper will deal with the topic of comparison of theoretical and experimental values of sun protection factors. The theoretical part includes basic theory related to the understanding of the subject of this thesis, theory related to sun protection products, their regulations, applications, impact on human health and the environment. In order to make it easier to understand the experimental part, we will define basic terms such as solar radiation, UV radiation, MED and SPF factor. The paper also deals with the numerical calculation of the SPF factor which will be used in the experimental part of the paper. In this work, we will briefly go through the basic techniques for determining sun protection factors in cosmetic products, with an emphasis on the SPF method used in the experimental part of the work. The experimental part includes the procedure for preparing sunscreen, calculating the concentrations of UV filters needed to obtain the desired factors, the production process, and finally testing and checking the matching of the results. The "in vivo" SPF method performed on a number of subjects is used as a testing method. The aim of this work is to compare the theoretical results obtained by calculating the concentration of UV filters that are required for a certain protection factor and the results obtained by experiment, that is, by the SPF method. Based on the comparison of the results, the conclusion of the comparison of theory and experiment will be made, whether there was a deviation and if so, what is the reason for it.