The article examines one of the main indicators of pension adequacy the replacement rate. The importance of using this indicator for pension system management is substantiated. A methodology for determining theoretical and empirical replacement rates is proposed in relation to the peculiarities of the Russian system of compulsory pension insurance. The article presents the results of calculations carried out on the model of the theoretical replacement rate developed by the authors, according to which, in the current Russian conditions, the replacement coefficient for an employee with a median wage and average length of service is more than 40%, which corresponds to the international criteria for the sufficiency of pensions for this indicator. However, with higher wages, for example, equal to the average for Russia and above, there is a lag behind the level of most EU countries. Modeling shows that in 2002—2018, there was an increase in the differentiation of pensions and replacement rates depending on wages. The performed forecast calculations for the period up to 2050 have revealed the following trends: a decrease in replacement rates for recipients of minimum and median salaries, approximate stabilization for average salaries and growth for recipients with high salaries. The article provides a number of examples of using the theoretical replacement rate for the analysis of the pension system in terms of the effect on the level of pensions: participation in the formation of pension savings, valorization, years of the insurance period, etc.