Personal income taxation in the Czech Republic has undergone significant changes in the last 20 years. Among main changes is replacing of deductions from the tax base with tax credits in 2006, as well as linking income tax and contributions on compulsory insurance in the form of so-called super-gross wage with the simultaneous introduction of a flat tax rate and introduction of maximum assessment bases for compulsory contributions in 2008. In this paper, we quantify the fiscal impacts of significant changes using macroeconomic and microeconomic approaches. We compare the results within each other, but also with the expected fiscal impact stated in the explanatory reports of the amending laws. The results show good consistency in estimates of the fiscal impact of tax and contribution reforms and confirm four fiscally significant reforms from 2000 to 2018. The expected negative and positive effects of changes in income tax presented in the explanatory reports are generally lower than in our calculations. Improving the quantification of fiscal impacts is essential for the adoption of an efficient and rational tax policy.
