The article describes and studies the modification of the model of the average income tax rate schedule for the case of a non-zero initial rate. Defining the input parameters is the most challenging step in the application of this model. The restrictions on the choice of input parameters of the proposed modification of the model are defined. Special attention is devoted to the choice of the elasticity pa-rameters in this model.
The obtained results allow to reduce the issue of defining the marginal income tax rates to the definition of the input parameters of the model. Moreover, the quantity of the pointed-out parameters this model out to be less than in the case of the direct choice of the marginal tax rates schedule.