Ethernet Cable Categories and Speeds Explained

Updated 5 November 2026 · Standard formula, shown below

Ethernet cable categories describe tested performance limits, not the speed your internet service automatically delivers. Cat5e supports 1 Gb/s over up to 100 metres, Cat6 supports 1 Gb/s over 100 metres and can carry 10 Gb/s over shorter runs, Cat6a supports 10 Gb/s over 100 metres, while Cat7 and Cat8 are shielded categories with different standards and shorter or more specialized uses.

What the Categories Mean

“Cat” is short for category. The number identifies a set of electrical performance requirements for a balanced twisted-pair cable, including frequency capability and limits on interference and signal loss. Higher numbers generally indicate tighter performance requirements, but they do not mean that every connection using that cable will run faster.

The cable is only one part of an Ethernet link. The network ports at both ends, their negotiated speed, the length and installation quality of the run, and the devices and service carrying the data all matter. A Cat8 cable plugged into two 1 Gb/s ports still makes a 1 Gb/s link.

Cat5e: A widely used choice for ordinary home and office Gigabit Ethernet.
Cat6: Offers more headroom against crosstalk; useful for Gigabit links and some shorter 10 Gigabit runs.
Cat6a: Designed for 10 Gigabit Ethernet across a full 100-metre channel.
Cat7: A shielded category defined in ISO/IEC cabling standards, but not a familiar TIA-recognized category for typical RJ45 Ethernet installations.
Cat8: A high-frequency, shielded option for short 25 or 40 Gigabit links, chiefly in data-centre environments.

Speed, Bandwidth, and Cable Length

Network speed is usually stated in bits per second: 1 Gb/s is one gigabit per second. It is not the same as file size, which is commonly measured in bytes; eight bits make one byte, before accounting for network overhead. A 10 Gb/s link therefore does not promise that a file will transfer at 10 gigabytes per second.

Frequency, measured in megahertz (MHz), describes the range of electrical signals a cable is specified to support. It is not a direct speed rating. Common figures are 100 MHz for Cat5e, 250 MHz for Cat6, 500 MHz for Cat6a, 600 MHz for Cat7, and 2,000 MHz for Cat8. Ethernet standards and cable limits are related, but a higher MHz figure alone does not establish a particular application’s actual throughput.

For conventional structured cabling, the familiar maximum channel length is 100 metres (about 328 feet), including the fixed cable and patch cords. Cat6 can support 10GBASE-T at shorter distances—often described as up to 55 metres under suitable conditions—but the achievable distance depends on cable quality, installation, and interference. Cat6a is specified for 10GBASE-T to 100 metres. Cat8’s 25GBASE-T and 40GBASE-T applications are limited to 30 metres, making it unsuitable as a general substitute for long building runs.

Comparing Cat5e, Cat6, Cat6a, Cat7, and Cat8

Cat5e: Commonly supports 1 Gb/s to 100 metres. It is often entirely adequate for internet plans and local networks that use Gigabit ports. It does not guarantee multi-gigabit performance simply because a newer router is installed.
Cat6: Supports 1 Gb/s to 100 metres and may support 10 Gb/s over a shorter run. It is a practical step up when new cabling is being installed, though it may not provide a full-length 10 Gb/s link.
Cat6a: Supports 10 Gb/s to 100 metres and is thicker and less flexible in many product designs than Cat6. It is useful where 10 Gb/s capacity over a full-length permanent run is a real requirement.
Cat7: Often sold with a shield and an RJ45-style plug, but the category’s connector and standards history differs from ordinary TIA structured cabling. A “Cat7” label alone does not ensure the cable and connectors form a standards-compliant Cat7 channel.
Cat8: Specified for high-speed, short-reach data-centre cabling, with 25 or 40 Gb/s operation up to 30 metres. It is usually unnecessary for home networks and does not make a standard home router faster.

How to Choose a Cable

Start with the ports and distance, rather than buying the highest category number. Check the speed supported by the router, switch, computer, dock, or other devices at both ends. The link is limited by the slowest relevant interface, and the internet connection may be slower still.

For existing Gigabit equipment: Cat5e is normally sufficient, provided it is in good condition and correctly terminated.
For a new home run: Cat6 is a common all-around option. Consider Cat6a if you specifically need 10 Gb/s across a run approaching 100 metres.
For data-centre links: Choose cabling based on the network equipment, distance, and applicable cabling design. Cat8 is intended for short, high-speed connections, not general long-distance wiring.
For outdoor or difficult routes: Select cable rated for that environment, such as outdoor, burial, or plenum-rated cable when the installation requires it. Category describes performance; it does not by itself certify environmental suitability.

Shielding, Connectors, and Installation

Many Cat5e, Cat6, and Cat6a cables are unshielded twisted pair (UTP); shielded versions also exist. Twisting the pairs helps reduce interference, while shielding can provide additional protection in particular electrically noisy settings. Shielding must be installed and bonded as intended; an ungrounded or poorly handled shield is not a universal improvement. For most ordinary home runs, correctly installed UTP is sufficient.

Ethernet cables commonly use an eight-position modular plug often called RJ45. The category is not determined by the plug alone: cable, plugs or jacks, termination, and the whole channel must meet the relevant performance requirements. Avoid sharp bends, crushed cable, untwisting the pairs excessively near a termination, and running data cable close and parallel to sources of electrical interference. Installation details can undermine a cable’s rated performance.

Common Misconceptions and Problems

A category rating is not an internet-speed promise. If a connection is slower than expected, check the negotiated link speed in the device or switch settings, confirm that every port supports the desired rate, and test with a known-good cable. A damaged connector, poor termination, or incorrectly configured port can cause errors or a link to fall back to a lower speed.

Another common misconception is that Cat7 is always better than Cat6a because its number is higher. Category labels belong to defined standards, and products advertised with a label may not follow the same connector or certification system. For typical RJ45-based building cabling, Cat6a is often a clearer, more practical route to a standards-based 10 Gb/s channel than buying an ambiguously labeled “Cat7” patch cable.

Likewise, a thicker or shielded cable is not automatically faster. It may be harder to route, and performance depends on the whole link and the applicable Ethernet standard. Do not pay for Cat8 unless the short-distance 25 or 40 Gb/s use case and compatible equipment justify it.

Frequently Asked Questions

Is Cat5e enough for a 1 Gb/s internet connection?
Yes. Properly installed Cat5e supports Gigabit Ethernet over a channel up to 100 metres. Your actual internet speed also depends on your service, router, device, and other network conditions.

Can Cat6 run 10 Gb/s?
It can support 10GBASE-T over shorter distances, with commonly cited limits of up to 55 metres under suitable conditions. For a 100-metre 10 Gb/s channel, Cat6a is the appropriate category.

Is Cat7 better than Cat6a?
Not automatically. Cat7 has a higher frequency specification and shielding requirements in its standards context, but its connector ecosystem differs from typical RJ45 installations. Cat6a is a straightforward choice for 10 Gb/s to 100 metres.

Does Cat8 make Wi-Fi or internet faster?
No. Cat8 only affects a wired Ethernet link and cannot raise the speed beyond the capabilities of the ports, network equipment, and internet service. It is designed for short, specialized high-speed links.

Can I use a higher-category cable with older equipment?
Generally, yes. Ethernet devices negotiate a speed supported by both ends, so a newer cable can be used with older ports. The connection will operate at the equipment’s supported rate, not the cable’s theoretical maximum.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.