How tall is a 25U rack?

A 25U rack has 43.75 inches (about 111 cm) of usable mounting height. The math is simple: one rack unit (1U) is 1.75 inches, so 25 x 1.75 = 43.75 inches.

Usable height vs overall height

The usable height is the space for equipment. The cabinet itself is taller because of the top panel, base, and frame. Most 25U enclosures measure roughly 48 to 55 inches overall, and casters or leveling feet add more. Check the maker's spec sheet for the exact number.

Rack height chart

Other rack dimensions to check

• Width: a 19-inch rack has a 17.75-inch opening between the mounting rails under the EIA-310 standard
• Depth: usually 24 to 42 inches, so confirm your deepest server fits with room for cables
• Type: an open-frame rack, a wall-mount rack, and a closed cabinet all use the same unit sizes

Before buying, measure the ceiling height, door width, and the path to the room where the rack will sit.