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.

Finally, consider your router. Many cheap routers only support Ethernet up to 100 megabits per second so that the router will bottleneck anything newer than Cat 5. Even the best home routers rarely support more than gigabit Ethernet, meaning Cat 6a and Cat 7 are of questionable use. If your ISP provides a slow, clunky modem/router combo, request an upgrade or purchase a standalone router with better connectivity.

With all of the above to consider, a Cat 6 cable is the one you’ll most likely need. Many homes can even get away with Cat 5e.

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. Cables bought for personal use rarely exceed 100 meters anyway and are unlikely to experience bottlenecked speeds.

Below, you can see the capabilities of each cable type.

Category Shielding Max Transmission Speed (at 100 meters) 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 1,000Mbps / 1Gbps 250 MHz
Cat 6a Shielded 10,000Mbps / 10Gbps 500 MHz
Cat 7 Shielded 10,000Mbps / 10Gbps 600 MHz
Cat 7a Shielded 10,000Mbps/10Gbps 1,000MHz
Cat 8 Shielded 40,000Mbps/40Gbps 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, but only do so 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. They’re proportionally more expensive than other Ethernet cables, though their performance translates to a premium price tag. Cat 7 cables reach up to 100Gbps at a range of 15 meters, making them an excellent choice for connecting modems or routers directly to your devices. Cat 7 cables are always shielded and use a modified GigaGate45 connector, which is backward compatible with regular Ethernet ports.

Cat 7a

Cat 7a currently offers the highest-specification Ethernet cables you can buy, but it’s not widely available and offers only a few supporting networking hardware options. Even more, the transmission speed is no different than Cat 7, yet Cat 7a cables improve 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; thus, you won’t find related products saturating the market just yet. This standard promises a maximum frequency of 2,000MHz and speeds of up to 40Gbps at 30 meters (~100 feet). 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.

Older specifications, like Cat 6a, enable four connectors for a total of five cables with a combined distance of 100 meters. Cat 8’s distance limitation ensures the 40Gbps speeds and related power requirements. Cat 8 cables are expensive, however, costing $16 for a three-foot cord, for example.

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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