The ideal cabinet elevation at which to install upper cabinets is determined by several factors, including the height of base cabinets, countertop thickness, backsplash height, and whether or not there is a range to consider. Then, depending on whether you're installing the cabinets before or after the base cabinets and countertop, how you measure this height will differ. The ideal upper Cabinet elevation will allow an average-height household member to reach those shelves standing without straining the back or arms or even climbing on a step-stool.