The article highlights the existing theoretical approaches to the definition of the term "purchasing power of the population" and the factors that determine it. The concepts of purchasing power of money, purchasing power of wages, minimum wage, subsistence level are considered. The relationship between purchasing power and inflation rates, consumer price index, stability of the national currency is shown. The modern view of the issue assumes a connection between purchasing power and economic activity, economic capacity, and economic stability. The indicators of purchasing power are determined on the basis of the balance of monetary income and expenditure of the population. On their basis, the demand for goods is formed, which has an impact on trade and production. The differences between nominal and real wages, statistical data on the average nominal wage of a full-time employee of enterprises, institutions, and organizations of Ukraine are considered. The existing theoretical and applied approaches to the realization of quantitative measurement of purchasing power are presented. A linear and quadratic mathematical model is constructed, describing the relationship between the purchasing power of the population of Ukraine and wages, taking into account the indices of perception of corruption and inflation. As a result of the study, a positive dependence of the purchasing power of the population of Ukraine on the average wage in 2011-2020 is revealed. Emphasis is placed on the current regional differentiation of the average wage and its differences in terms of economic activity in Ukraine. The importance of using the proposed approaches in the development of measures to increase the purchasing power of the population and strengthen regional cohesion is justified. Steps to reduce regional disparities and strengthen regional cohesion measures will improve economic activity and economic sustainability, primarily in terms of increasing employment and stimulating business development. 

mathematical model, wages, household income, purchasing power of the population, inflation index, corruption perception index