The article explores the complexities of educational scale-making. "Educational scales" are defined as the spatial and temporal orders generated as pupils and teachers move and are moved through educational systems; scales are "envelopes of spacetime" into which certain schoolbased identities (and not others) can be folded. Scale is thus both an object and a means of power in educational practice. Using data from life history interviews with an elementary teacher in the USA, the article illustrates the multiplicity of scale-making processes, and raises the question of how certain scale definitions become more widely accepted and authoritative than others. (Contains 5 notes.)