The present invention comprises a retractable rule assembly that includes a housing assembly and a reel rotatably mounted in the housing assembly. An elongated blade formed of a ribbon of metal is mounted on the reel. One end of the blade is connected to the reel. The blade is constructed and arranged with respect to the housing assembly to extend from a position tangential to the reel outwardly through a spaced opening in the housing assembly. A coil spring that is formed of a ribbon of metal has a construction and arrangement between the housing assembly and the reel to rotate the reel in the housing assembly in a direction to wind the elongated blade about the reel when the blade is extending outwardly of the housing assembly opening. The blade has a "normal" concavo-convex cross-sectional configuration when extended and has a flat cross-sectional configuration when it is wound about the reel so that the wound reel is disposed about the reel in an abutting volute coil formation. A blade holding assembly is provided which can hold the blade in any position of extension outwardly of the housing assembly opening and to release the blade from any position in which it is held. The blade has a width in its flattened configuration thereof within the range of 1.10''-1.5'' and a height in its concavo-convex configuration thereof within the range of 0.25''-0.40''.