The article analyzes the specific features of calculating the value added tax base, some complexities and problems in its determination, and focuses on the issues of improving the formation of the tax base. In addition, based on the results of applying the changes and additions made to the determination and calculation of the value added tax base, relevant conclusions are drawn and recommendations are developed.

This article examines the scientific foundations of the methodology for determining the value added tax base on a margin basis. It analyses the substance of the margin approach introduced in Uzbekistan from 2026, its legal and methodological foundations, as well as the main practical problems and ways to address them. The study proposes the necessary conditions for the effective application of the margin-based tax base, an algorithm for VAT calculation, and a five-criteria filter for extending this approach to other segments. It also discusses the experience of the European Union and the United Kingdom, focusing on fiscal neutrality, documentation discipline, and control indicators in the application of the margin scheme. The article develops conclusions and proposals aimed at the scientifically grounded improvement of the margin-based VAT base methodology in Uzbekistan

Studying the administration of value-added tax in our country is also related to the improvement of value-added tax. The article analyzes the specific features of calculating the value-added tax base, some complications, and problems in its determination, and focuses on issues of improving the formation of the tax base. In addition, based on the results of applying the changes and additions to the determination and calculation of the value-added tax base, relevant conclusions were formed and recommendations were developed.