Server Rack Size Guide

Server Rack Size Guide

Most business owners do not anticipate the wide range of server rack size options until they choose the right one. Buying the right server rack can be daunting sometimes, especially if you do not understand server rack sizes. Sadly, it is not as simple as small, medium, or large, as is the case with most other items. Since there are multiple uses for server racks, there are multiple size options to accommodate all use cases adequately. However, if you learn about a few key size variables, you will be able to decide which rack size suits your needs best. Of course, it is always better to consult expert professionals like Communications Solutions Inc. in Jacksonville, Florida, for the best size options that suit your needs. That being said, let’s discuss the key size variables in our server rack size guide, to help you better choose the right size of server racks for your business.

Server Rack Size Guide

The standard unit for server rack sizing is “U,” which is used to measure the height of a server rack. This standard unit comes from the “rack units” or “U-spaces” that the height provides, and each “U” is 1.75-inches tall. As you will learn ahead, height matters more than other size variables.

You need to consider the key variables when selecting the right server rack size for your business or server room.

1. Height

The standard unit of server rack sizes comes from the height as it is the main factor to consider because it is the main classifying factor of server rack sizes. The standard height of data center racks is 48U or a 7-foot rack. However, sometimes, they also use 42U serve racks.

This is because server racks are small enough to provide easy access to equipment while large enough to allow future expansion. For the same reason, a standard “half rack” for data centers is typically 22U or 27U.

However, you need to note that not all businesses require data center standard sizes or heights, so plenty of non-standard sizes are available in the markets. Open-frame racks, in particular, may sometimes be as small as 5U and go up to 70U.

Such open-frame server racks are versatile due to their lightweight design and easy access. On the other hand, enclosed racks can also have non-standard sizes, and currently, the 18U and 37U non-standard sizes are the most popular among enclosed server racks.

2. Depth

The depth of a server rack is the next key size variable. Server rack depth is not measured in U but in typical inches. The depth of server racks can go up to 50-inches. Typically, you will see 24-inch, 29-inch, and 48-inch as the norm or standard.

There aren’t too many non-standard variations in server rack depth because these three can get the job done for most business needs. For example, a rack with a 24-inch depth is ideal for housing patch panels, AV equipment, and network equipment.

Major companies like Cisco, Dell, IBM, and HP typically use 29-inch deep open-frame racks for housing popular servers. The larger server rack with 48-inch depth is typically used for housing equipment bigger than those mentioned, storing accessories, or cable management.

Typically, when you opt for server racks with large depths, you get adjustable rails that help you mount smaller or shorter equipment steadily.

3. Width

Another key size variable is the width of the server rack. The most common rack width in the IT world is 19-inches, so it is the standard width. For this reason, most servers and other devices come with a mounting width of 19-inches from side to side.

The standard server rack width of 19-inches allows you to fit these devices perfectly. The space makes installation easy because you don’t have to worry about measuring individual components of the equipment and figuring out how to fit them in an ideal way.

You can mount them directly because the rack can fit the entire device easily. Server racks with an internal width of 19-inches typically have an exterior width of 24 inches. This width is provided because standard server rack floor panels in data centers are 24-inches x 24-inches.

This design makes installing the server racks easy without losing ease of access or equipment manageability. The standard external width of 24-inches can comfortably and efficiently use up the available floor space with only a single floor panel.

This floor space makes it much simpler for data centers to add monitor equipment, cables, and PDUs, by efficiently utilizing the available space on edge.

4. Rack Type (2-Post or 4-Post)

The last key size variable to consider is rack type. A 2-post server rack has two vertical upright support beams, whereas a 4-post rack has four instead. As you would expect, the main difference is that 2-post racks support less weight and depth.

Typically, a 2-post server rack is ideal for lighter tech and accessories that don’t need much depth, like routers, patch panels, switches, and telecommunication equipment. For heavier equipment, you will have to consider 4-post racks.

However, if you get 2-post server racks with the ideal height, width, and depth for your growing business, you can always convert it into a 4-post rack using a caster kit when your needs grow heavier. Just remember that 2-post server racks have stringent weight and depth restrictions.


These were all the key size variables for server rack sizes. While this server rack size guide can help you better understand server rack sizes, you must look at your business needs to know what should be the size of the server racks you need.

Consider your server room, equipment, overall set-up, layout, and installation needs thoroughly before deciding what size suits your needs best. It is also highly recommended that you keep future needs in mind when planning for such tech-based installations.

A half-rack may be ideal if you have a small business or office that requires limited equipment. Whereas if you run a large business with a dedicated server room, your requirements will be different, and you may need larger server racks with different size variations.

Regardless of what size rack you determine is right for you, it is always important to consider your limits, layout, and server room/ cabinet safety.

We highly recommend consulting expert professionals like Communications Solutions Inc. in Jacksonville, Florida, for your server rack, server room, business network, and telecommunication solutions.

If you want to learn more about our server rack size guide or the best business network or telecommunication solutions for your business, Contact Us Today!



Let us connect your business to technology today!

Recent Posts