In this paper we present a computer-based model (so-called European Tax Analyzer) for the international computation and comparison of company tax burdens. The methodology follows the forward-looking concepts for the measurement of effective average tax rates (EATR) on the basis of a model-firm. The EATR is computed for investments generating economic rents (i.e. pure profits above the market interest rate). In contrast to the prevailing approaches for calculating EATR based on separate and isolate investment projects the model-firm approach allows to calculate EATR for more complex and realistic conditions that are relevant for the decision making. Due to its flexibility another important advantage of the model-firm approach is the possibility to include the most relevant and complex provisions of the tax codes (i.e. tax systems, taxes, tax rates, and tax bases). A concrete computation and comparison of the EATR of corporations and their shareholders in five different countries reveals the wide spread between the national EATR. Moreover, for the time series 1995-2000 it could be shown that the differences between the EATR have declined a little. In spite of this convergence, however, tax distortions of competition did not become significantly less.