What's the Difference Between Cat5e, Cat6 and Cat7 Ethernet Cables?

Stand in front of a wall of Ethernet cables and they all look much the same: a plug, a length of cable, a price tag that varies more than you'd expect. But the "Cat" number printed on the sheath makes a real difference to speed, reliability and future-proofing — and buying the wrong one either wastes money or quietly bottlenecks your network.

Here's what those numbers actually mean, and which cable you should buy for the job in hand.

"Cat" is short for category, a set of standards defining how much data a twisted-pair cable can carry and how well it resists interference. The higher the number, the more bandwidth the cable supports and the better its shielding tends to be. Each new category is backwards-compatible — a Cat6 cable works fine in a Cat5e setup — so you never need to worry about a newer cable refusing to talk to older kit.

Two figures matter when comparing categories:

• Speed (or data rate) — the maximum throughput, measured in megabits or gigabits per second.
• Bandwidth — the frequency range the cable supports, measured in MHz. Think of it as the width of the pipe: more bandwidth means more headroom for data.

Cat5e ("e" for enhanced) replaced the original Cat5 standard and remains the most common cable in UK homes.

• Speed: up to 1 Gbps
• Bandwidth: 100 MHz
• Best for: everyday home networking

For most households, Cat5e is genuinely all you need. A gigabit connection comfortably outpaces the vast majority of UK broadband packages, handles 4K streaming without breaking a sweat, and gives you a stable, low-latency link for gaming that Wi-Fi can't match. It's also thin, flexible and cheap, which makes it easy to route around skirting boards and door frames.

The catch? It's the least future-proofed option, and its modest shielding makes it more susceptible to interference on long runs through electrically noisy areas.

Cat6 tightens the specification considerably: the internal wire pairs are twisted more tightly, and most Cat6 cables include a plastic spine (called a spline) separating the pairs to cut down on crosstalk — the interference between wires inside the cable itself.

• Speed: up to 10 Gbps over runs up to about 55 metres; 1 Gbps at the full 100 metres
• Bandwidth: 250 MHz
• Best for: new installations, home offices, NAS drives and anyone planning ahead

The price gap between Cat5e and Cat6 has shrunk to the point where, for a new setup, Cat6 is usually the smarter buy. If you're transferring big files to a NAS drive, backing up computers over the network, or expect to upgrade to multi-gigabit broadband in the next few years, Cat6 gives you headroom that Cat5e simply doesn't. It's slightly thicker and stiffer, but for home distances that rarely matters.

There's also Cat6a ("a" for augmented), which sustains 10 Gbps over the full 100 metres at 500 MHz bandwidth. It's the go-to for offices and larger properties, though the cable is noticeably chunkier.

Cat7 is where cable construction gets serious. Each of the four wire pairs is individually wrapped in foil, and the whole bundle gets an overall screen on top — a double layer of protection that keeps interference out and your signal clean.

• Speed: up to 10 Gbps at the full 100 metres
• Bandwidth: 600 MHz
• Best for: demanding installations, interference-prone routes, and maximum peace of mind

That comprehensive shielding is Cat7's superpower. If your cable has to share space with mains wiring, run past fluorescent lighting or appliances, or snake through a garage or workshop, Cat7 shrugs off electrical noise that can degrade lesser cables. The generous 600 MHz of bandwidth also gives it more headroom than Cat6a, and the robust construction stands up well to the knocks of a permanent installation — it's a genuine fit-and-forget cable.

Consumer Cat7 cables come fitted with standard RJ45 plugs, so they slot straight into your existing router, switch and devices with no adapters needed, and they're fully backwards-compatible with everything else on your network. For most homes Cat6 or Cat6a remains the value pick, but if you're wiring somewhere electrically noisy — or you simply want the most heavily shielded cable on the shelf so it never has to be thought about again — Cat7 delivers.

And if you're building for serious speed over short distances, there's Cat8 — 25–40 Gbps over runs of up to 30 metres, the choice for server racks and high-end home labs.

• Replacing a single cable behind the telly? Cat5e is fine — your broadband is the bottleneck, not the cable.
• Setting up a home office, media server or new house wiring? Buy Cat6. The small premium buys years of headroom.
• Long runs through walls, or a larger property? Cat6a sustains full 10 Gbps speeds over distance.
• Cable running beside mains wiring, through a workshop, or anywhere with heavy interference? Cat7's full shielding makes it the fit-and-forget choice.

Two final tips. First, a chain is only as fast as its slowest link — a Cat6 cable won't speed anything up if your router or switch only has gigabit ports. Second, quality matters more than category at the budget end: look for cables marked with solid copper conductors rather than "CCA" (copper-clad aluminium), which underperforms and can run warm on powered (PoE) connections.

Get those two things right, and whichever category you choose, your network will be doing everything the cable allows. Explore Maplin's full range of RJ45 Ethernet Cables today to get started!