Ethernet Cable Speed Depends on Length and Category, With Cat6 Exception

The 328-foot allowance includes more than the cable itself, and about 11 cable categories exist depending on classification. Cat1 is for old analog telephone lines, and Cat1 through Cat4 can be eliminated for typical modern networking, such as connecting a gaming rig to a Wi-Fi 7 tri-band router.

A typical setup uses 295 feet of solid-core cable plus up to 33 feet of flexible patch cables at either end, according to the article. Within that distance, a solid Cat5e or Cat6 cable can support 1 Gbps Ethernet. In the average scenario, a 10-, 25- or 100-foot Ethernet cable should not slow down connection speeds. Cable length becomes more consequential when running faster-than-gigabit speeds.

Cable type determines the limit. Cat5e and Cat6 can support 1 Gbps at up to 328 feet. Cat6 can support 10GBASE-T, or 10 Gbps, but its full 10 Gbps rating extends only to about 180 feet. Cat6a is designed to sustain 10GBASE-T up to 328 feet, making it the better alternative for a longer 10 Gbps run.

Going beyond a cable's rated distance will not necessarily produce a gradual slowdown. With Cat6, for example, 10 Gbps is specified for 180-foot runs, but a longer run may still produce 10 Gbps if the installation and cable are in great shape. If a Cat6 cable is slightly longer than 180 feet and produces errors and inconsistencies in performance, the advice is to step up to Cat6a.

For most installations, the guidance is to use a tested Cat5e, Cat6 or Cat6a cable that is 328 feet or shorter between two active network devices. Cable type and length should be chosen based on the plan with the Internet service provider. If a plan maxes out at 1 Gbps, a Cat8 cable is unnecessary; Engadget compared that to purchasing an Nvidia GeForce RTX 5090 to play Roblox. Cat7 or Cat8 is not automatically better for every scenario because router ports and computer capabilities also need consideration.

If two devices are more than 328 feet apart, an extra-long Cat6 or Cat6a cable is not always the best solution. An Ethernet switch can be placed at the midpoint to create two separate copper runs, or the long portion can be replaced with fiber optic cable. Fiber does not connect directly to copper, but a media converter or a fiber-capable switch solves that conflict.

For Power over Ethernet, length is more of a concern. The same 328-foot rule generally applies, but lengthy runs may not provide enough power. The applicable cable should always be used, and the PoE requirements of the switch and the devices should be verified. Ethernet can ordinarily run at full speed up to 328 feet when the cable category supports that speed, with Cat6 being the only exception in the article's list. For Cat6, the recommendation is to stay at 180 feet or less.

Editor's Summary Ethernet cables generally hold their rated speeds up to 328 feet, but the limit varies by category, with Cat6 limited to about 180 feet for 10 Gbps. For longer high-speed links, Cat6a, an Ethernet switch or fiber may be required, and PoE runs need power verification.