Cabinets should be chosen according to the width-depth-length of the devices which will be mounted into the rack cabinet. 600x600, 600x800, 600x1000, 800x800, 800x1000 are the standard sizes of the models. That would be the most suitable depth if rackmount server will be mounted into the rack cabinet. When calculating the height of a cabinet, height of the each device which will be mounted into the cabinet should be calculated and %20 of the total height should be added for the potential expansion. ( 1U=44,45mm ). Formrack 19” Rack Cabinet heights are:12, 16, 20, 26, 32, 36, 39, 42, 44U.