This article explores how professionals within the Norwegian immigration authorities conceptualise age when doing non‐medical age assessments. By using social constructivism, which challenges an ethnocentric quantifying understanding of age, we delve into how socially constructed perceptions of childhood and adulthood manifest in assessment practices and the implications of these. By examining how applicants’ physical appearance, body language and life experience are used as an assessment basis, we argue that the ways age is conceptualised relate to Western ideas and ideals while overlooking other social and cultural backgrounds in which age is embedded.