Abstract: A tension gauge for indicating the tension on a fastener such as a mine roof bolt is a non-metallic right circular cylinder having a central bore and an axial thickness between parallel top and bottom surfaces. A plurality of radially extending holes is equally spaced around the perimeter of the cylinder, an end of each hole in communication with the bore and/or an end opening in the perimeter of said cylinder. Preferably, there are six such holes disposed at 60.degree. intervals about the cylinder bore. The central axis of each hole lies in a plane which is parallel to and substantially equidistant from the planes of the top and bottom surfaces.The cylinder is formed of a one-piece, compressible, organopolymeric material, such as high density polyethylene, which is capable of flowing under compression resulting from tension on the fastener less than that tension which will overstress the fastener.