<p>Researchers have been interested in measuring well-being with the Capability Approach (CA) over the past decades. However, most studies have not measured well-being at the individual level. This diverges from the fundamental theoretical attributes of conceptualizing well-being from the individual perspective. Further, the substantial cost of conventional measurement methods limits their scalability and precludes frequent updates. This paper explores a novel approach to measuring multidimensional well-being at the individual level for large or even entire populations within a city and its surrounding rural areas. Drawing upon the CA and the successful Human Development Index (HDI), this paper proposes a new exploratory Individual Multidimensional Well-being Index (IMWI) using innovative e-governance big data. The IMWI consists of three dimensions according to the HDI and seven indicators representing basic, enhanced, and deprived capabilities. An empirical study in Changshu, eastern China, demonstrates the potential of our methodology to enhance understanding of individual well-being across a large sample (<i>n</i> = 957,251). It captures multiple inequalities, explores the correspondence between dimensional and aggregated well-being, and reveals distinct clustering patterns. Moreover, the well-being results can be cost-efficiently updated. The IMWI has the potential to serve as a valuable tool for municipal governments across diverse socioeconomic contexts to measure citizens’ well-being and inform public policy. This paper adds to the debate on “the approach espouses a principle of each person as an end”, as well as on the application of the CA and emerging big data.</p>