What are the Standard Server Rack Dimensions?

When organizing a data center or a small home office, everyone needs furniture for accommodating network equipment. It doesn’t matter how big your system is, still, special, durable bodies are manufactured for IT hardware.

In 2024, the industry offers a wide range of models for any kind of data center since infrastructures gain high popularity and demand. They differ in design, configuration, and size, starting from compact models for desktop installation up to huge models for large data centers. It is important to pick the furniture of the optimal size to accommodate all the needed devices, route cables, and leave free space for air circulation.

A server rack has long been a most of any telecommunication network. It stands as a guard of expensive equipment, which provides the required level of security. It can even be vandal-proof. Furniture pieces also successfully do not allow moisture, dirt, and dust to pass inside. Racks prevent expensive computing hardware from damage and malfunction caused by temperature changes.

Correctly selected telecommunication furniture is one of the guarantees of uninterrupted operation. Open-frame server racks are designed to provide an excellent opportunity for housing the required equipment. They help make the SCS (Structures Cabling System) maintenance process comfortable and orderly. To achieve maximum efficiency and ensure convenient access to all operating parts, take a responsible choice of the model. Server racks come in a huge range of sizes, and there are a few general requirements that should be met by server furniture manufacturers. Thus, below, let’s find out the answer to the question “how wide is a standard data equipment rack”, and consider dimensions used in server equipment measurement.

Standard Server Rack Dimensions

IT hardware is used to store datum and cope with computing tasks. The size of a system can total from a dozen up to a hundred of active equipment. Thus, when selecting a suitable server rack size, system administrators should consider the following server cabinet dimensions:

Height

This dimension may be unclear for unskilled users. In system administration, height is identified in units (U). Usually, it is specified as 12U, 15U, or 42U in the specs. 1U is equal to 1.75 inches. To calculate the height of the cabinet in centimeters, users should multiply 1,75×12/15/42/etc.

An Example of Choosing an Optimal Height

In a 9U wall-mounted cabinet, you can place only 9 patch panels, each of them is 1-unit high. The model can freely house these devices, since this passive hardware is classified as small. If you do not plan to expand the data center in the near future, with the correct and high-quality organization of cables and equipment, you will get that very ideal option.

A completely different situation for your future SCS will arise if the apparatus suffers from quick heating during operation. Server enclosures often face overheating problems. For example, if you need to place 6 2U or 12 single-unit items, then a 19` 12U server furniture will never be the best solution.

Why? The answer lies on the surface. Free space between equipment and cables is required to efficiently exhaust hot air to the outside. Overheating can not only destabilize the entire system, but also completely render it inoperative. A 19` 15U network rack is more suitable here. If necessary, it will allow installing additional ventilation shelves, and free space will help passive cooling work for you.

Width

Beginning from 2000s, manufacturers produce models of standardized widths. Datacenter equipment racks are normally 19 inches wide, which is considered the standard server rack width. There are also 24-wide products. This width is chosen to accommodate all modern equipment and fasten devices to racks.

Depth

Depth is the third important criterion. So, what is the standard server rack depth? This dimension is variable and can range from 0 to 50 inches. The standard depth of server racks is 24 or 48-inches. When dealing with racks, it is possible to adjust the depth as you need, since posts can be reassembled.

Mounting cabinets with a depth of 23–31 inches are suitable for switches, patch panels, and other small-sized equipment, and models with a depth of 40–47 inches are suitable for servers.

Here, the thing is that complete and actual depths exist. Note that “actual depth” is a few centimeters less than the listed one, since internal posts takes little space. Still, this rule is not a universal rule. It’s best to check the manufacturer’s specifications for accurate dimensions. You should take into consideration the actual indicator.  It is measured from inner posts and usually a few centimeters less than a complete depth.

When calculating an optimal depth of the required model, note that about 2 cm from the front and rear sides of the mounted equipment should be left for cable routing and ventilation. Devices should not tightly fit the rack mount.

2 VS 4 Post Rack Models

Server furniture is used as reliable storage of telecom equipment. Nowadays, manufacturers produce two main types of server furniture. According to the number of vertical uprights, they distinguish between 2- and 4-post models. When considering the standard server rack size, you should keep in mind the following information about enclosure designs:

2-post models are limited in depth since only two vertical uprights are used for mounting. Typically, such models are used to fasten accessories and passive hardware, such as routers, switches, patch panels, etc.

When it comes to 4-post products, they are much deeper. They can house more hardware and ensure fitment of large servers and other active devices.

Yet, both models can be equally tall. 2-upright racks can be as tall as 4-post models. It is easy to convert a 2-post rack into a 4-upright model with the use of a caster kit.

Examples of Standard Server Racks & Cabinets Sizes

Let’s see how server network rack sizes explained to browse the catalog of offered products.

• 4U desktop and wall-mount rack. This is a compact 4-post rack with removable sidewalls and doors. It has a 19” width and 24-inch depth. Due to its small size, it is perfect for small rooms and offices.
• 24U 4-post floor-standing cabinet with removable panels and doors. This model has a bigger load capacity and can accommodate more devices. Yet, it is not suitable for fastening to the wall. The rack is equipped with casters to make it movable.
• 48U 4-post 19” data rack sizes. This is a huge box for large data centers. It has all the needed tech slots for cable routing and fan installation. The model allows accommodating multiple servers, routers, PCs, and other types of passive and active equipment.

In the 2020s, the market offers a wide variety of models, including wall-mounted, open-frame, enclosed, etc. So, it is possible to select a furniture piece to any demand. Yet, the main thing is to know what size you need.

How to Calculate the Correct Size of a Server Rack?

Here’s a guide on how to identify the required server rack cabinet dimensions:

1. Measure all devices that you plan to house inside the rack.
2. Think out the layout. If possible, make a 3D layout to visualize the scheme and identify possible mistakes.
3. Judging by the layout, calculate how tall, wide, and deep the needed cabinet should be.
4. When selecting the width, check the compatibility of the cabinet with hardware. Make sure that mounting rail or chassis will be exactly wide to fasten and support hardware.

Important Remarks to take into Account

Note that when defining the needed server rack size, several rules must be observed:

System administrators always leave free space in the cabinet. When the size is calculated, add a quarter of the figure (or even half of the size) to ensure leaving extra space. This is done due to two reasons:

• Network systems usually expand over time. So, workers leave extra space for the future installation of additional equipment. While 25-50% of free space is left for future expansion, experts also recommend to leave 1U-2U between devices for cabling.
• Sufficient cooling and free air circulation. Devices are never placed tightly; otherwise, they exchange generated heat and overheat quickly. It is necessary to leave space between operating units.

Foresee the rack cooling system when calculating server cabinet sizes. While open racks rely solely on natural airflow, additional cooling solutions like fans or air conditioners may be necessary in some cases, depending on the heat load within the rack. If it is an open-frame rack, the natural airflow will be enough to cool hardware. If it is an enclosed design, leave space for fan installation.

Manufacturers offer advanced solutions, such as liquid cooling, for efficient heat removal from server cabinets. Such systems use a network of tubes, in which liquid is circulating. Cold water is supplied to server racks and takes heat, and hot water leaves the enclosure, after which it enters a reservoir, where it’s stored until cooled again. After that, it’s ready for repeated circulation.

Think about cable management. How will cords be wired and where?

Manufacturers produce different types of furniture, including floor-standing and wall-mount solutions and open-frame or enclosed constructions. The range of network rack dimensions differs greatly. It is possible to pick a model for any system and room. Yet, make sure to foresee all the aspects to arrange the best system and ensure its smooth and uninterrupted running.

To conclude, note that you should have at least an approximate layout (and better a precise one) of hardware allocation inside the rack to calculate all three above-mentioned data center rack dimensions, pick the best model, and organize the system setup correctly. To make the right decision and achieve an excellent result from the procedure for choosing the optimal server rack for your telecommunication network, we recommend that you first consult with specialists. They will help you not miss even the most insignificant, at first glance, trifles, so that you are satisfied with the result obtained for solving your problems.