Abstract: A pipe fitter's square has a plurality of linear edges oriented at selected angles to provide easy and accurate alignment of pipe sections. A first edge of the square is parallel to its longitudinal axis. Second and third edges of the square are positioned at 45.degree. angles to the first edge to provide for 90.degree. pipe section alignment. Fourth and fifth edges of the square are positioned at 22.5.degree. angles relative to the longitudinal axis of the square to allow alignment for a 45.degree. bend. Levels are mounted to the square parallel and adjacent to the respective first, second and third edges to provide references to the horizontal and vertical and to make possible the division of pipe exteriors into equal angular sections. A protractor scale is imprinted on the square and a pivotal protractor arm is mounted on the square to measure specific angles.