This paper discusses the multifaceted challenges associated with translating the concept of human mobilities into practical application within the realm of international planning. Additionally, it introduces the utilization of a scientific index methodology as a viable solution to address these challenges. Although scientific indices are not commonly employed in planning practices, they prove to be well-suited for the structured operationalization of intricate phenomena, such as mobility. Following a concise theoretical overview, this paper systematically outlines the process of operationalizing a social science-based concept of mobility to create an index. To facilitate this endeavor, a theoretical framework for a Mobility Index is constructed, and a comprehensive list of essential indicators required for its computation is developed, drawing from international research. Subsequently, this spatial mobility index is computed using accessibility and user survey data from a district in Berlin, Germany. The outcomes of this index are then visually depicted on maps, offering a clear representation of disparities in mobility options across the studied area. Consequently, the mobility index introduces an innovative approach for planning professionals to identify variations in human mobilities within their study areas, facilitating more informed decision-making.