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How to choose an Ethernet cable

Megabits, Cats, and cables get a bit confusing when you are looking at Ethernet cables. Figuring out which works for you without going overboard is hard, but we’re here to help. 

We’ve defined these terms and put together tables comparing the benefits and issues with each. We’ll explain what shields do and why you may — or may not — need them. So, start here when figuring out how to choose the best Ethernet cable for your home or work.

How do you choose?

Image of Ethernet port and lpug.
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The easiest way to select a cable is to pick one with the range and performance you need.

But what do you need?

Start with the speed of your home internet connection. If you have gigabit internet (1Gbps), an old Ethernet cable will hold you back. If you have a slower connection — perhaps 10 or 20 megabits per second — you’re good with anything Cat 5 or newer.

If you don’t know your internet subscription’s actual speed, connect your PC directly to the modem and load this speed test. Doing so will give you a starting idea of what you’ll need in terms of wired connectivity. If your subscription only supports 50Mbps downloads, purchasing a 1Gbps Ethernet cable is simply overkill — at least for now.

Next, consider the speed needed for your network. This knowledge is irrelevant to most home users. Still, if you frequently move big files between computers or stream extremely high-bandwidth video, a better Ethernet cable can make a huge difference. If that’s not the case and you only surf the internet’s shallow waters, you don’t need a fast in-homer network.

As today’s routers become faster and more capable, facilitating faster network speeds, you need more capable cables to take full advantage. If you are looking for a replacement cable, it’s a good idea to choose one of the more recent versions, to both take advantage of speeds and future-proof your setup for years to come: That usually means picking a Cat 6a or even a Cat 8 cable. On its own, the Ethernet cable won’t make a big difference, but it can work together with other high-end network devices to ensure that your connection is as strong as possible.

Shielding and foil wrapping

Beyond Cat 6, all Ethernet cables are also shielded to reduce interference, but it’s important to understand how that shielding works.

Shielding cables are covered with a layer of grounded foil that helps prevent electromagnetic interference. In the modern house, with plenty of Wi-Fi signals, Bluetooth connections, and appliance activity, unshielded cables can run into interference and distortion issues. This is especially true for Ethernet cables that are run for longer distances — so shielding quickly becomes important in more complex setups, which is why it became a mandatory part of the standard.

Typically, the foil wrapping is bound around each twisted pair of wires within the Ethernet cable, since this can also help reduce “crosstalk” or signal pollution between the twisted pair itself. However, more advanced versions may also add a foil shield as an inner layer of the cable sheath, for maximum protection.

What does ‘Cat’ mean?

When shopping for cables, you may notice they’re nearly always classified as “Cat-5,” “Cat6e,” or something similar. “Cat” simply stands for “Category.” The number that follows indicates the specification version supported by the cable.

A general rule of thumb is that higher numbers represent faster speeds and higher frequencies, measured in megahertz (MHz). As is the case with most technologies, newer cables typically support higher bandwidths, and therefore increased download speeds and faster connections.

Keep in mind that longer Ethernet cables have slower transmission speeds. This is why Ethernet cables tend to have two-speed ratings, one at 10-30 meters and one at 100 meters: Since the 100-meter rating doesn’t matter outside of very large professional projects, we suggest just focusing on the 10-30 meter numbers.

Below, you can see the capabilities of each cable type (we’re skipping categories 1, 2, and 4, as they are not technically recognized as Ethernet standards and have no application today).

Category Shielding Max Transmission Speeds  Max Bandwidth
Cat 3 Unshielded 10Mbps 16 MHz
Cat 5 Unshielded 10-100Mbps 100 MHz
Cat 5e Unshielded 1,000Mbps – 1Gbps 100 MHz
Cat 6 Shielded or Unshielded 10Gbps up to 55 meters 250 MHz
Cat 6a Shielded 10Gbps up to 55 meters 500 MHz
Cat 7 Shielded 100Gbps up to 15 meters 600 MHz
Cat 7a Shielded 100Gbps up to 15 meters 1,000MHz
Cat 8 Shielded 40Gbps up to 30 meters 2,000MHz

Cat 3 and Cat 5

Both Cat 3 and Cat 5 Ethernet cables are, at this point, obsolete. You’ll still find Cat 5 cables in use, but you should avoid them altogether. They’re slow and discontinued.

Cat 5e

The “e” in Cat 5e stands for “enhanced.” There are no physical differences between Cat 5 and Cat 5e cables. However, manufacturers build Cat 5e cables under more stringent testing standards to eliminate unwanted signal transfers between communication channels (crosstalk). Cat 5e is currently the most commonly used cable, mainly due to its low production cost and support for speeds faster than Cat 5 cables.

Cat 6

Cat 6 cables support higher bandwidths than Cat 5 and Cat 5e cables. They’re tightly wound and usually outfitted with foil or braided shielding. Said shielding protects the twisted pairs of wires inside the Ethernet cable, which helps prevent crosstalk and noise interference. Cat 6 cables technically support speeds up to 10Gbps for up to 55 meters. That speed comes with a price, however, as Cat 6 cables are more expensive than Cat 5 and Cat 5e variants.

Cat 6a

The “a” in Cat 6a stands for “augmented.” Cables based on this standard are a step up from Cat 6 versions by supporting twice the maximum bandwidth. They’re also capable of maintaining higher transmission speeds over longer cable lengths. Cat 6a cables come shielded, and their sheathing — which is thick enough to eliminate crosstalk — makes for a much denser, less flexible cable than Cat 6.

Cat 7

Cat 7 cables support higher bandwidths and significantly faster transmission speeds than Cat 6 cables by utilizing the newest widely available Ethernet technology. Cat 7 cables reach up to 100Gbps at a range of 15 meters making it one of the most capable categories of Ethernet cables. Cat 7 cables are always shielded and use a modified GigaGate45 connector, which is backward compatible with RJ45 Ethernet ports.

That modified GG45 connector is a proprietary component though, and while the backward compatibility helped a little, there are still issues with following previous Ethernet standards. This led to most manufacturers avoiding the Cat 7 standard, which is why it’s quite rare today. That difficulty led to the development of Cat 6a, and a lot of marketing confusion, since some sellers started referring to Cat 6a as the new Cat 7. Always check the specs before you buy — and when in doubt, we suggest just going for Cat 8 instead.

Cat 7a

Cat 7a currently offers one of the highest-specification Ethernet cables you can buy, but it’s not widely available and offers only a few supporting networking hardware options. The 7a standard was designed to support 40 Gigabit Ethernet connections up to 50 meters and — just like Cat 7, but with improvement to the overall bandwidth — more than 50%. This improvement may be useful in some instances, but Cat 7a cables are far more expensive than any other option. Consider using Cat 7a only in very niche cases.

Cat 8

Cat 8 is an emerging technology, although cables are currently available for purchase. This standard promises a maximum frequency of 2,000MHz and speeds of up to 40Gbps at 30 meters. That high frequency requires shielding, meaning you’ll never find unshielded Cat 8 cables. Even more, Cat 8 supports two connectors. Thus it only allows for three connected cables with a combined length of 30 meters. Cat 8 cables will cost more than other options, but they have become more affordable these days: You can find options for a 10-foot Cat 8 cable under $15.

Cat 8 is also the only cable to meet the latest IEEE standards (the aforementioned 40Gbps and 2,000MHz frequency), which is one reason it’s a great choice for future-proofing, despite the significantly higher costs. As an added bonus, it also skips the connector mess of Cat 7.

Ethernet glossary

Ethernet IP address

The differences between the various types of Ethernet cables are rather simple, but some of the terminologies can be confusing. To help out, we put together a quick rundown on what the different terms mean, and what you should expect when buying cables with those designations.

Cat: Short for “category.”

TP (Twisted Pairs): Refers to how the wires inside twist together. Twisted Pairs are an industry standard, and are only inferior to fiber-optic cabling in terms of maximum length and speed drop-off.

UTP (Unshielded Twisted Pairs): These cables won’t have foil or braided shielding. That means they’re more flexible and cheaper to produce, but you’ll sacrifice signal quality and increase vulnerability for crosstalk.

STP or SSTP (Shielded Twisted Pairs): Braided shielding protects these cables. Usually made of copper or another conductive polymer, shielding reduces noise and improves connection quality.

FTP or SFTP (Foiled Twisted Pairs): Foil shielding protects these cables, which helps to reduce noise and improve connection quality.

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