The appliance dimensions of a cooktop are not the same as the cutout dimensions needed to install it. The appliance dimensions, shown in the above image, are the length and width of the cooktop surface that sits above your countertop. The cutout dimensions are the length and width of the opening in the countertop needed for installation. Cutout dimensions are always smaller than the appliance dimensions because cooktop surfaces extend beyond the cutout below for a more seamless integration with your countertops.