Server racks are denoted by the height, width and depth. Rack form factors are often classified by the width of the front panels, typically 19”, but also 10”, 23” and ETSI format.

[](/network/20210531_define-19in-rack-1.png “https://www.racksolutions.com/news/blog/server-rack-sizes/” =400x)

The available capacity is then determined by the height of the rack, measured in rack-units (1U represents 1.75” across 3 holes).

[20210531_250px-server_rack_rail_dimensions.svg.png](/network/20210531_250px-server_rack_rail_dimensions.svg.png “https://en.wikipedia.org/wiki/19-inch_rack” =x400)

Depths are more dependent on OEM standards, which is typically around 29”. Audio racks tend to be shallower between 19” and 24”. Browse a rack store for market prices.