Purpose: This research investigates Portuguese manufacturing companies' Industry 4.0 (I4.0) maturity perception level and proposes an index to measure that aim.Design/methodology/approach: This study uses a survey method to gather the companies' perceptions of their I4.0 maturity level and applies subsequent exploratory factor analysis to propose a global I4.0 measurement index.Findings: The research results show that the most critical factors in evaluating the perception level of I4.0 Perception Maturity (IPM) are strategy, leadership, and customer experiences. The result for the Global Index was 53.50%. Hence, the global Index companies' perception of the level of maturity of I4.0 in Portugal is medium.Research limitations/implications: This study encompasses only Portuguese manufacturing organizations (50 valid responses). Moreover, the research is subject to the limitations of the survey methodology, such as possible respondent bias.Practical implications: The Portuguese I4.0 strategy mainly targets small and medium-sized enterprises through a bottom-up approach. Hence, companies need proper methodologies and tools for evaluating I4.0 adoption, identifying their present situation concerning I4.0 and where to focus on improving the process and achieving the intended benefits.Social implications: This research identifies the main perceived benefits and obstacles of adopting I4.0, suggesting avenues for its successful implementation by the Portuguese companies.Originality/value: This study provides a valuable tool for manufacturing companies to identify the factors that need to be improved to create significant growth in the I4.0 Perception Maturity (IPM) index. Therefore, it can support companies in establishing a roadmap for successful I4.0 adoption and improving their performance and competitive position accordingly.