The article examines the practical use of the approach to modeling the progressive income tax schedule in relation to the assessment of tax revenues to the budget. The problem of constructing a model income distribution function has been solved. According to statistics, various hypotheses were tested on the law of the distribution of citizens' incomes. As a result, the hypothesis of a lognormal distribution was adopted. The calculations show that, in the case of using the optimal progressive income tax schedule in Russia, revenues should increase by approximately one and a half times.