A guide for cutting paving slabs comprises: a guide member (1) for guiding a cutting tool; a clamping means (5, 6); and a locator (3). The clamping means comprises a spindle (5) which passes through an opening in the guide member and connects to the locator. The clamping means is adjustable to adjust the position of the spindle relative to the guide member thereby to adjust the distance between the locator and the guide member.