What is the maximum Ethernet cable length to not lose signal?

While many of us connect to WiFi to browse the web, most WiFi routers require a hard-wired Ethernet connection to connect you to the Internet. But how long can an Ethernet cable be before its performance suffers?

What is the maximum length of an Ethernet cable?

Ethernet cables can be of any length, but there comes a time when the distance the signal has to travel becomes too long. Even if the signal can travel some distance, the time it takes to get from A to B can become so long that end users have to deal with very slow connection speeds.

So how long can an Ethernet cable be before the signal is lost?

In general, standard Ethernet cables (that is, the twisted pair Ethernet cable most people are familiar with) reach 328 feet (100 meters) in length before their speeds suffer. This is the case for cable at room (or ambient) temperature and generally refers to most of the usual repeater conditions. Businesses, offices, and many industries can use longer Ethernet cables.

This is because the long cable makes signal transmission more difficult due to the increased resistance. Resistance is a phenomenon on an electronic circuit in which a material resists an electric current. In an Ethernet cable, the copper wire acts as the electrical conductor. As the length of the wire increases, the resistance also increases.

As the resistance increases, the speed of the signal starts to decrease. This is where connection strength, latency, and bandwidth can be affected. The farther the signal travels, the lower the bandwidth and speed, and the higher the latency.

However, this maximum number can vary greatly depending on the type of Ethernet cable in question. So let's discuss the different maximum lengths of different types of Ethernet.

Ethernet cable length

The 3 main types of Ethernet cables are:

1. Fiber Optic
2. Coaxial
3. Twisted pair

These cables differ in material composition and construction. While coax and twisted pair cables use copper wire, fiber optic cables use very thin glass fibers, like the ones shown below.

What is the maximum Ethernet cable length to not lose signal? Picture 1

Fiber optic cable transmits data in the form of light, increasing connection speed. There are many reasons why fiber optic cable is better than copper cable, with the increased speed being just one benefit.

Because of this key difference, fiber optic cable has a different maximum length than coaxial and twisted pair cables. According to Router Switch's blog, a single fiber optic cable can extend up to 2,000 meters (or 6,581 feet) at 10Mbps and 100Mbps.

On the other hand, coax cable can reach a maximum distance of 500 meters, according to Cisco Press. In the same vein, Cisco Press also claims that twisted pair cable can only reach a distance of 100 meters (328 feet).

Does Ethernet cable generation affect signal strength?

What is the maximum Ethernet cable length to not lose signal? Picture 2

The answer to this question is a bit complicated

Ethernet cable generation has an effect on signal strength, but most ordinary people will not encounter a situation where calculating specific Ethernet cable resistance becomes an issue. According to the official guidelines of ANSI/TIA/EIA 568-B, the maximum allowable cable length for twisted pair Ethernet cable is 90m.

So in a nutshell, the longer the Ethernet cable, the more likely you are to experience data transmission problems.

It is important to note that fiber optic cables do not fall into these categories. They can reach longer distances due to the interior made of fiberglass. In addition, coax cable is also not included in the Cat classification system.

Micah Soto

Update 09 August 2023