If you’ve ever browsed cables online, you’ve probably noticed that they’re nearly always classified as Cat-5, Cat6e, or something similar. “Cat” simply stands for “Category,” and the number that follows indicates the specifications to which the cable was manufactured. A general rule of thumb is that the higher numbers represent faster speeds and higher frequencies, measured in Mhz. As is the case with most technologies, newer cables tend to support higher bandwidths, and therefore increased download speeds and faster connections.
Keep in mind that longer Ethernet cables will result in slower transmission speeds, though cables bought for personal use rarely exceed 100 meters; and so are unlikely to experience much speed drop-off.
Below, you can see what each cable type is capable of.
| Category | Shielding | Max Transmission Speed (at 100 meters) | Max Bandwidth |
| Cat 3 | Unshielded | 10 Mbps | 16 MHz |
| Cat 5 | Unshielded | 10/100 Mbps | 100 MHz |
| Cat 5e | Unshielded | 1,000 Mbps / 1 Gbps | 100 MHz |
| Cat 6 | Shielded or Unshielded | 1,000 Mbps / 1 Gbps | 250 MHz |
| Cat 6a | Shielded | 10,000 Mbps / 10 Gbps | 500 MHz |
| Cat 7 | Shielded | 10,000 Mbps / 10 Gbps | 600 MHz |
| Cat 7a | Shielded | 10,000 Mbps/10 Gbps | 1,000Mhz |
How do you choose?
The easiest way to select a cable is to pick the one with the range and performance you need. But what do you need?
Start with the speed of your home internet connection. If you have gigabit internet, an old Ethernet cable will hold you back. But if you have a slower connection, say 10 or 20 megabits per second, you’re good with anything Cat 5 or newer.
Next, consider the speed you need for your network. This is frankly irrelevant for most home users. But if you move big files between computers frequently, or you stream extremely high-bandwidth video content, a better Ethernet cable can make a difference.
Finally, consider your router. Some cheap routers only support Ethernet up to 100 megabits per second, so it will bottleneck anything newer than Cat 5. Even the best home routers rarely support more than gigabit Ethernet, so Cat 6a and Cat 7 are of questionable use.
With all of the above to consider, a Cat 6 cable is the one you’ll most likely need. Most homes can get away with Cat 5e.