Abstract: A guide for a portable power tool such as a circular saw, a saber saw, a router, or the like, for effecting a straight cut in a work. The guide is clampable upon the work, such as a wood plank, and is provided with an angularly adjustable bracket forming a straight edge for guiding the power tool. An adjustable and clampable gage is supported by the bracket, the gage having a reference edge surface adjustably movable away or towards the straight edge of the bracket to define a distance from the bracket edge equal to the distance separating the guiding edge of the power tool support platform from the cutting path of the power tool. When it is desired to effectuate a cut along a scribed line on the work, the straight edge of the bracket is located along the scribed line, and a second line is marked at the location of the reference edge surface of the gage.