In a first aspect the guide for power tools has a pair of guide members each having a straight guide edge and a connecting arrangement connecting the guide members with the straight guide edges opposed, parallel and separated. The connecting arrangement is such that the separation of the straight guide edges is variable. The connecting arrangement is fixable at a set separation. The opposed, parallel and separated straight guide edges guide opposed sides of a hand power tool in use. In a further aspect a guide for power tools includes an aim line for a line with an intended cut. The aim line is operable between a first condition in which it is supported parallel to and spaced a preset distance from the straight guide edge of a guide member, for aligning with an intended cut path, and a second condition in which the aim line is supported outside the field of the cut. The aim line provides accurate alignment of the power tool guide prior to cutting.