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Does a Long Ethernet Cable Reduce Internet Speed?


As the Depeche Mode song goes, everything counts in large amounts when it comes to having a fast and reliable Internet connection. One question that often comes up is whether the length of an Ethernet cable can impact Internet speed. It’s definitely an interesting question and one worth exploring in greater detail.

How Ethernet Cables Work:

The inner copper wires inside an Ethernet cable

Before we explore the impact of cable length on Internet speed, it would be helpful to understand a bit about how Ethernet cables work. Ethernet cables are used to connect devices to a local area network (LAN) or the Internet. They are made up of four pairs of copper wires that transmit data using a method called twisted pair signaling. The wires are twisted together in a specific pattern to help reduce interference and crosstalk, which can affect the quality of the signal.

Ethernet cables are classified according to their speed and performance capabilities. The most common types are Cat5, Cat5e, Cat6, and Cat6a. These cables can support speeds of up to 1 Gbps, 1 Gbps, 10 Gbps, and 10 Gbps, respectively.

The Role of Cable Length:

So, can the length of the Ethernet cable impact your Internet speed? The short answer is, yes. That being said, it’s not the most significant factor. In general, the longer the cable, the more the signal can degrade. However, this degradation is generally minimal and is unlikely to be noticeable as long as the wire is within the distance limit specified by the cable standard.

Ethernet cable distance limits

The following table shows the distance limits of various Ethernet cable standards for a specific speed. For example, a CAT 6 cable is good for 1 Gbps up to 55 meters and a cat 6a cable is good for 1 Gbps up to 100 meters.

Ethernet StandardCATDistance Limit
10BASE-T3100 meters
100BASE-TX5100 meters
1000BASE-T5e100 meters
10GBASE-T655 meters
10GBASE-T6a100 meters
100GBASE-T730 meters
The distance limit of common Ethernet cable standards

Real-World Considerations:

In the real world, for pretty much all practical situations, using a longer Ethernet cable will not slow down a connection, as long as it is within the distance limit specifications.

The really important thing to focus on is the distance limits. This distance is the sum of the distance of your patching cable from the host to the data point and the patch frame to the switch.

The time taken for electrons to travel 100m on a Cat5e wire is approximately 500 nanoseconds: 100 m / (0.64 * 3 * 10-8 m/s)

An IPv4 packet header has a time to live after which a packet is dropped if there is no response

A bigger issue is that weak signals on a long wire can result in packet loss. Due to the nature of TCP, once the network layer sees that a checksum has failed, it will ask for that packet again. This failure, request for the same packet and retransmission will lead to a more noticeable slowdown.

If you’re using an older or lower-quality Ethernet cable, the impact of cable length on internet speed may be more noticeable. However, even in these cases, the impact is likely to be minimal.


The length of your Ethernet cable will only have a minimal impact on your Internet speed as long as your wire is within the length specifications. More important is ensuring signal strength remains strong and on the cable front, what you can do is ensure that you are using high-quality Ethernet cables. This will help you avoid packet loss which significantly slows down your speeds.

A software engineer, I have a strong interest in technology, bot software and hardware. Blogging is a way to share what I have learned and hopefully people will find it useful.