The article examines methodological and practical aspects of analyzing and calculating the key financial indicators (ratios) of business entities. It analyzes the specific features of the methodology for their calculation as presented in current methodological documents approved at the ministerial level. The primary focus is on problematic issues that may arise for expert economists when conducting research related to the calculation of key financial indicators, the most significant of which is the impact of current legislation on the calculation algorithm itself. Particular attention is given to changes in the structure of financial reporting, the data of which serves as the informational basis for conducting forensic economic examinations in this area. Based on the transformation of financial statement items (lines), an algorithm is proposed for calculating the key financial indicators (ratios), taking into account the current requirements of the National Accounting Standard 1 “General Requirements for Financial Reporting”. Emphasis is placed on evaluating the calculated financial and economic indicators (ratios) of an enterprise or organization based solely on interim reporting data: for a quarter, half-year, or nine months. Attention is also drawn to the need to verify the accuracy of the financial statement data. Thus, a qualitative approach at the initial stage of the examination and the proper transformation of the calculation algorithm for financial indicators, in accordance with the requirements of current regulatory documents, allow expert economists to significantly reduce the time needed to conduct forensic examinations in this field and help to mitigate the fact that the methodology for calculating financial indicators has not been updated for a long time.