Finished wood thickness is 5/8” so the interior width and height is 1.25” less than exterior dimensions. The solid back with the integrated mounting cleat is 1/2” with a 3/4” cleat for a total interior depth of less 1.25”. for our Media and Storage cabinets with sliding doors, subtract another 3/4” for the doors, total is less 2” for back and doors combined. Contact us if you have questions