To choose the right server rack cabinet, you need to know its height in rack units (U), as well as select the appropriate width and depth for your equipment. Rack units are used to describe the height of servers, switches, patch panels, and other equipment mounted in 19″ or 10″ racks/cabinets.

What is a rack unit (U) and how many centimeters is it?

1U = 44.45 mm (≈ 4.445 cm). The designation 1U always refers to one rack unit.

Height diagram of 1U for a 19″ server rack

Rack units are applied to equipment installed in wall-mounted cabinets and floor-standing cabinets according to the EIA-310 standard. To calculate the height, multiply the number of U by 44.45 mm. For example, 44U ≈ 1955.8 mm (about 2 m).

Where to start when choosing a server rack cabinet

  • Width. The 19″ format means an internal distance between rails of 482.6 mm. The external width of the cabinet is usually 600 or 800 mm. The 10″ format has an internal width of 254 mm and an external width of about 310–360 mm (compact wall boxes).
  • Depth. Focus on the usable depth between the rails, not just the external dimension. For example, if the external depth of the cabinet is 400 mm, the usable depth will be around 300 mm — this is the dimension you should use to choose shelves and equipment. Typical values: wall-mounted cabinets — 350/450/500/600 mm; floor-standing cabinets — 600/800/1000/1200 mm.
  • Height. Add up the height of your devices in U (switches, patch panels, UPS, shelves) and add 30–40% spare space for ventilation and future expansion. Example: 5U of equipment ⇒ choose a 7–9U cabinet.

Types of server rack cabinets

  • Wall-mounted 19″ cabinets — height 4–22U, depth 350–600 mm, load capacity 60–100 kg. Ideal for offices, access points, and small server rooms.
  • Floor-standing 19″ cabinets — height 24–48U, depth 600–1200 mm, load capacity 600–1000+ kg. Used in server rooms and data centers.

Useful options to consider

We recommend taking into account: removable side panels, door type (glass/perforated/metal), adjustable rails, cable organizers, fan mounting options, grounding, locks. For offices, IP20 is sufficient; for dusty or humid environments — IP54+.

Such a cabinet can accommodate switches, routers, servers, storage systems, uninterruptible power supplies, and accessories.

❓ Frequently Asked Questions 

❓ What is a rack unit (U) and how many centimeters is it?

1U = 44.45 mm (≈ 4.445 cm). This is the standard height measurement for equipment in 19″ and 10″ cabinets.

❓ What is the difference between 19″ and 10″ cabinets?

19″ — internal width 482.6 mm, external width 600 or 800 mm.
10″ — internal width 254 mm, external width 310–360 mm.

❓ How to choose the height?

Add 30–40% spare space to the total height of your equipment in U.

❓ How to choose the depth?

If the external depth of the cabinet is, for example, 400 mm — the usable depth will be around 300 mm. This is the dimension to use for selecting shelves and equipment, considering extra space for connectors and cable bending.

❓ Wall-mounted or floor-standing cabinet?

Wall-mounted — compact, for offices. Floor-standing — spacious, for server rooms.

❓ Which additional options are important?

Door type, panels, rails, organizers, IP20–IP54+ rating.

💡 Tip: Visit the server rack cabinets catalog and choose a model for your equipment with future needs in mind.