Abstract: A multi-functional gauge comprised of a frame, an adjustment seat, a scale and a magnet assembly. The frame includes a chamber for receiving the adjustment seat and the depth rod, and a base extending toward one side of the frame for maintaining the stability of the frame and accommodating the magnet assembly. The adjustment seat includes an indicator plate, a depth rod, a lock screw and a lock knob which are threadedly engaged with each other. The scale is longitudinally secured on the frame, and along the scale the adjustment seat can be set in position or loosened for free movement by the threading engagement of the lock screw and the lock knob. The adjustment seat is provided with at least one window which corresponds to the scale so that the scale can be read therefrom, and a tongue which extends from the wall of the window. The magnet assembly includes a magnet, iron plates and an insertion element.