You'll get precise, actionable answers in under 60 seconds: A 6U cabinet is exactly 10. 5 inches (267 mm) tall —not 6 inches—and follows the standard 19-inch rack width. It's designed for wall mounting in compact spaces like telecom closets, security control rooms, or small office. Confused by 'U' (Rack Units) when looking at data cabinets? Use the following table to work out the height of a cabinet in inches, centimetres or feet based on the U height. Please note that the height of the cabinet/rack stated here is the useable internal 'working' height of the cabinet/rack. Standard sizes available for sale: Width: 600, 800 mm for convenient. But for network cabinets, we use “U” instead. 45 millimeters, if you prefer metric). This standard was created by the Electronic Industries Alliance, or EIA.