Does a Longer Ethernet Cable Affect Speed?

When setting up a wired internet connection, one question often pops up: Does the length of an Ethernet cable affect internet speed? It’s a fair concern, especially if your modem is far from your workstation. Let’s break down the facts and clear up any confusion about cable length, speed, and performance.

Yes, Ethernet cable length can affect speed, but in most home or office setups, it won’t. As long as you're within the recommended length limits for your Ethernet cable type, the impact on speed and latency is negligible.

There are different types of Ethernet cables, commonly labelled as Cat5e, Cat6, Cat6a, Cat7, and Cat8. Each supports different speeds and maximum lengths:

If your Ethernet cable is under 100 metres (about 328 feet) and you're using a Cat5e or better, you're unlikely to see any drop in speed due to cable length.

• Speed: Up to 1 Gbps

• Bandwidth: 100 MHz

• Maximum Length: 100 metres

• Use Case: Still widely used for home and small business networks, Cat5e supports gigabit speeds and is cost-effective.

Cat5e improved upon the older Cat5 by reducing crosstalk (signal interference between wires), making it more reliable for faster connections.

• Speed: Up to 10 Gbps (for distances under 55 metres)

• Bandwidth: 250 MHz

• Maximum Length: 100 metres (1 Gbps); 55 metres (10 Gbps)

• Use Case: Ideal for modern networks where gigabit speed is standard, especially in office environments.

Cat6 Ethernet cables are more tightly wound and often include a spline (separator) to reduce crosstalk further, making them more robust than Cat5e.

• Speed: 10 Gbps

• Bandwidth: 500 MHz

• Maximum Length: 100 metres

• Use Case: Data centres, enterprise networks, and environments needing high-speed data over longer distances.

Cat6a Ethernet cables are typically shielded, which reduces interference and makes them bulkier but more durable for demanding conditions.

• Speed: 10 Gbps

• Bandwidth: 600 MHz

• Maximum Length: 100 metres

• Use Case: High-end professional and industrial environments.

Cat7 Ethernet cables use shielding on each wire pair and the overall cable, making them excellent at rejecting electromagnetic interference (EMI). However, they are less common due to proprietary connectors and higher cost.

• Speed: 25–40 Gbps

• Bandwidth: 2000 MHz

• Maximum Length: 30 metres

• Use Case: Primarily used in data centres and server rooms for ultra-high-speed connections over short distances.

Cat8 is the newest standard and is fully shielded. It supports fast data rates but is not practical for most home networks due to limited range and higher cost.

Ethernet uses copper wiring, and over very long distances, the signal weakens—a process called attenuation. However, the standards above are designed to account for this. Problems usually only arise if:

• You exceed the recommended cable length.

• You’re using poor quality or damaged Ethernet cables.

• There’s excessive electromagnetic interference.

In such cases, the result is not just slower speed but also increased packet loss or connection instability.

Packet loss in networking occurs when one or more data packets travelling across a network fail to reach their destination. This leads to slower speeds, lag in real-time applications like video calls or gaming, and a generally unstable connection.

Cable length can technically increase latency—but we’re talking fractions of milliseconds. For example, even a 100-metre Ethernet cable only adds about 0.5 microseconds of delay. That’s imperceptible to humans and inconsequential for most applications, including gaming and streaming.

• Stick with Cat6 or higher for future-proofing and higher speeds.

• Avoid exceeding 100 metres unless you're using special equipment like repeaters or switches.

• Use shielded Ethernet cables (STP) in environments with heavy electrical interference.

In typical home or office use, the length of an Ethernet cable will not noticeably affect your internet speed—as long as the cable is under 100 meters and of good quality. If you're running a cable across a large space, just check the type and make sure it fits your needs.

So go ahead and plug in that long Ethernet cable across the house—your connection will still be strong.