An optical lapping guide for determining an amount of lapping performed on a row of sliders in a process for manufacturing sliders for magnetic data recording. The optical lapping guide is constructed with a front edge that is at an angle with respect to an air bearing surface plane ABS plane, such that a portion of the lapping guides is in front of the ABS and portion of the lapping guide is behind the ABS. As lapping progresses, an increasing amount of the lapping guide will be exposed at the ABS and visible for inspection. Therefore, after a lapping process has been performed, the optical lapping guide can be inspected to determine the amount of material removed by lapping. The greater the amount of the lapping guide that is exposed and visible, the greater the amount of material removed by lapping.