Counter depth is key to functional, comfortable kitchen design. Standard dimensions keep cabinetry within reasonable size for average-height users, and in relation to common sink and appliance sizes, but guidelines allow for slight or moderate changes. The countertop overhang plays a couple of roles and affects counter depth.
Based on Bases
Standard lower, or base, cabinets are 24 inches deep, while upper, or wall, cabinets are 12 inches deep. Countertops typically overhang their base cabinets by about 1 inch, or at least 3/4 inch beyond the drawer fronts and cabinet doors. The overhang helps keep crumbs and spills from getting into drawers and cupboards below and completes the comfortable cabinetry contour that includes a 3-inch-deep toe kick at the floor. Island or bar-style overhangs often extend about 15 inches or more to create knee space for people seated at the bar. Deep overhangs require bracing, which may be provided by brackets, legs or even a steel plate underneath the countertop.
Counter and Backsplash Height
Standard counter height is 36 inches, but for easier use, consider building up a section to accommodate a tall user or lowering a section for shorter users or someone in a wheelchair. The backsplash is installed after the countertop is in place -- if it's not an all-in-one unit -- and should extend at least 4 inches up the wall but, for maximum protection and appeal, could extend to the upper cabinets.