Widespread procedures to measure what is taken to be kinship condition negotiations of various forms of belonging (family, ethnicity, nation, race, or even humanity). Kinship measurements require indicators, evidence, and persuasive display to become institutionalized. These measurements’ generative force enables their translation into differentiated access to resources. Kinship measurements pull together different, and even sometimes contrasting, ideas, practices, and materialities. Different measurements can add up, mutually reinforcing each other, and reach thresholds for inclusion or exclusion; but they most often remain contested, produce gradual results and do not achieve closure. Grouping them together around detecting closeness and similarity, we explore the productivity of kinship measurements in diverse settings, such as medicine, bureaucracy, and ritual, to demonstrate how they shape inequalities and marginalizations.