A tape measure includes a case with an opening, a core inside the case, a spring extending around and imparting a radially inward force to most of a circumference of the core, and a graduated free metal tape with an arcuate cross-section that is wound around the core between the core and spring. The free metal tape is not connected to the case and core and its entire length is passable through the opening. The spring urges the tape flat against the core. The tape may be graduated on both sides. The case may include rollers that roll on an external periphery of the tape wound around the core and that are urged radially inward by the spring, and plural slots in which respective axes of the rollers are displaced in response to a change of diameter of the external periphery of the tape wound around the core.
