In the context of today’s transition to the digital economy, almost all companies realized they need to undergo digital transformation, i.e., change their approaches to business processes based on digital technologies, which required significant funding. Yet not all companies understand and can assess the economic effect of digitalization, especially because they have limited financial resources due to the lockdown and some other factors. To solve this problem, the author developed a methodological approach to assess and forecast the effects the digital transformation may have on the company’s competitive ability based on the economic and mathematical simulation. This approach allows for the assessment of the digitalization levels of management, operational, and support processes and their effects on the competitive ability. The approach is based on such principles as comprehensiveness, structuredness, and measurability, as well as the econometric methods like the dynamic and expert ones, standardization, and the calculation of integrated indicators. The approach allows for obtaining relevant quantitative assessments and demonstrating how much the digitalization of management, operational, and support processes impacts the competitive ability of the company. This makes this approach feasible in practice. This approach is a management tool for the digital transformation of a company. It can be used in high-tech industrial enterprises to improve the feasibility and efficiency of management decisions. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.