Abstract: A radius router guide having a pair of spaced legs arranged for receiving a piece of material at an end of the material where a radius is to be cut. The legs are connected to a track arrangement which slidably supports a router, and the legs are also attached to the workpiece itself in such a manner as to pivot about an appropriate axis for cutting a desired radius on the workpiece. The router slides back and forth as it swings about the pivot axis of the legs so as to form a radius on the associated end of the workpiece. At least one of the legs is adjustably mounted on the track arrangement to permit varying the spacing between the legs so as to accommodate material of different widths.