A large number of publications devoted to a new class of materials - high-entropy alloys (HEA), is associated with their unique chemical, physical and mechanical properties both in cast materials and in various classes of coatings and refractory compounds. As a result of the research, the features of solid-soluble high-entropy alloys based on BCC and FCC phases have been revealed. These include the role of the most refractory element in the formation of the lattice parameter, the relationship of distortion with elastic deformation, and the contribution of the enthalpy of mixing to the strength and modulus of elasticity.  This made it possible, on the basis of Hooke's law, to propose a formula for determining the hardness of the HEA based on the BCC and FCC phases. Based on the fact that with an increase in temperature in high-entropy alloys, the values of the modulus of elasticity, distortion and enthalpy of mixing will obey the same laws, a formula is proposed for determining the yield strength depending on the test temperature of solid-soluble HEA based on BCC and FCC phases. A formula based on the role of the most fusible metal in the alloy is proposed to calculate the melting point of solid-soluble materials.