How far can you run an Ethernet cable?

Last Updated on March 13, 2021 by Dave Farquhar

How far can you run an Ethernet cable? The limit is around 90-100 meters. You can generally push that limit harder with CAT6 than with CAT5e, and there are ways you can cheat. Here’s how.

You may be able to buy an Ethernet cable longer than 100 meters, but don’t assume that just because you can buy one that it will work.

How far can you run an Ethernet cable? And why is there a limit?

How far can you run an Ethernet cable?
Generally the longest you should try to run an Ethernet cable is 90-100 meters.

Electrical signals degrade over long distances, especially when you’re talking super-thin wires like the ones in Ethernet cables. The faster we push data, the more sensitive the data becomes to that degradation.

Sprawling corporate campuses sometimes use fiber optics to get around the limits of Ethernet cable. When you cover long distances, fiber is often cheaper than all the extra equipment necessary to do the job with copper. That said, if you’re wiring your house, fiber is overkill. In most houses, CAT5e or CAT6 cable is more than fine.

Will a longer run slow me down?

Longer runs within reasonable limits don’t slow you down. And we’re talking reasonable limits here. Gigabit over a 3-foot run is the same as over a 300-foot run. That said, slowing down to a slower form of Ethernet can increase the practical limits of your run. You’re more likely to get away with a too-long run at 100-megabit or 10-megabit speeds.

How do I count the length of my run?

How to count your run matters. You’re not limited to 100 meters total. The limit is 90-100 meters to the switch. So if you have to do multiple long runs to reach a switch in the middle of your house or building, that’s OK. If I somehow had two computers both 90 meters from my switch, they can still talk to each other over that switch. And if that switch is another 90 meters to my router, both computers will still be able to reach the Internet.

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