Cat6 vs Cat6a vs Cat7 vs Cat8:
which cable do you actually need?
The category number on the box is a less reliable signal than the marketing suggests. Here's what each category actually guarantees, which ones are real standards versus invented tiers, and what to buy for what scenario.
The honest table
| Category | TIA standard? | Guaranteed speed | Practical reach |
|---|---|---|---|
| Cat5 | Yes (obsolete) | 100 Mbps | 100m, but no one should buy this |
| Cat5e | Yes | 1 Gbps | 100m at 1 Gbps; 2.5 Gbps usually works up to ~25m |
| Cat6 | Yes | 1 Gbps at 100m, 10 Gbps at 55m | The home-network floor in 2026 |
| Cat6a | Yes | 10 Gbps at 100m | Properly shielded; future-proof for 10 GbE service |
| Cat7 | No (not TIA) | Marketed as 10 Gbps; actually unverified | Avoid — it's a marketing tier, not a US standard |
| Cat7a | No (not TIA) | Same as Cat7 marketing | Same avoidance |
| Cat8 | Yes | 25 / 40 Gbps | 30m max; data-center cable, not home |
Notice what's not on the table: any claim that a higher category number automatically means a better cable. Cat6 is fully sufficient for 1 Gbps everywhere and 10 Gbps over most home runs. Cat6a adds proper shielding and full-length 10 Gbps support. Cat7 isn't recognized by the TIA at all — it's a marketing label some cable manufacturers slap on shielded cables, often shielded poorly, often using non-standard GG45 connectors that don't fit consumer ethernet ports.
The decision tree (just buy these)
If your service is up to 1 Gbps:
Cat5e is technically sufficient. Cat6 costs 20% more, future-proofs you for 2.5 GbE or 5 GbE service the day your ISP offers it, and the difference at the cash register is negligible. Buy Cat6.
Buy: Cat6 (UL-listed, pure copper, unshielded for indoor runs)
If your service is 2 Gbps or you expect to upgrade in the next 5 years:
Cat6 is fine for any single run under 55 meters (~180 feet) at 10 Gbps. For longer runs or for in-wall runs where you don't want to redo work later, step up to Cat6a — properly shielded, fully 10 Gbps end-to-end at the full 100 meter spec distance.
Buy: Cat6a (shielded if shared conduit with electrical)
If you're a data center or running 25/40 GbE between servers:
Cat8. It exists for this. Don't use it at home — the shielding makes it stiff, the connectors are pickier, and at home runs it's overkill that costs more without delivering anything you can use.
Buy: Cat8 only if you actually have 25 GbE+ hardware on both ends
If a sales page says 'Cat7':
Skip it. There's no TIA Cat7 standard. The cable inside may be perfectly good Cat6a, or it may be marketing-only shielding over a Cat6 conductor. You can't tell from the label. Cat6a from a reputable brand is cheaper and verifiable.
Buy: Cat6a from a known brand instead
What 'shielded' actually means
Ethernet cables come in two basic flavors: unshielded twisted pair (UTP) and various shielded variants (STP, FTP, S/FTP). Shielding reduces interference from external sources — power lines, motors, microwaves, fluorescent lighting — and reduces crosstalk between the four pairs inside the cable.
For home runs that pass through walls and don't sit next to high-current electrical wires, unshielded Cat6 is fine. Shielding adds cost, stiffness, and complication (proper shielded cabling requires grounded keystone jacks and grounded patch panels — if you don't ground the shield, you've made the cable worse, not better). For most homes, unshielded Cat6 or Cat6a delivers everything a properly- shielded run would deliver, at lower cost.
Shielded cable becomes worth it when: you're running cable in conduit shared with electrical lines, you live in a dense apartment building with massive ambient RF, or you're installing in a commercial environment where grounding infrastructure already exists.
How to verify the cable you bought is what it says it is
Cable counterfeiting is real. A box labeled Cat6 may contain copper-clad aluminum (CCA) conductors instead of solid copper, which doesn't meet the spec and will fail at gigabit speeds over any meaningful distance.
Three signals that a cable is legitimate:
- UL listing or ETL verification. The jacket should print a UL or ETL mark with a verified category number. No marking = no verification.
- Conductor stamping. Run a few inches of the cable and look at the printing on the jacket. It should specify the category, the conductor material ("Bare Copper" or "Pure Copper" — never "CCA"), the manufacturer, and a date code.
- Conductor weight. Pure copper cable is noticeably heavier than CCA. A 1000-foot box of real Cat6 copper weighs about 30 pounds; CCA weighs roughly half.
For in-wall installations specifically, a basic RJ45 cable tester (affiliate) catches the most common termination errors — missing pairs, swapped wires, broken conductors. They cost $15-30 and pay for themselves the first time they catch a bad cable before you close up a wall.
When to use solid-core vs stranded
Two construction types, different use cases:
- Solid-core cable runs the conductor as a single solid copper wire. Better signal characteristics over long distances, easier to terminate into punch-down blocks and keystone jacks. Use it for any cable that goes inside walls or ceilings — the "permanent" runs.
- Stranded cable uses many thin strands twisted together. More flexible, survives bending and unbending. Use it for the "patch" cables that connect a wall jack to a device — the short cables that get moved around.
Buying bulk solid-core Cat6 (affiliate) or Cat6a (affiliate) spools — 500 to 1000 feet — and short pre-terminated Cat6 patch cables (affiliate) for the device end is usually the most cost-effective pattern for a whole-house install.
What category to use where
A practical room-by-room read for a typical home install:
- Office (where the high-bandwidth work happens): Cat6a if 10 GbE service is plausible in the next 5 years, otherwise Cat6.
- Living room / media room: Cat6. Streaming and gaming don't need 10 GbE.
- Bedrooms with smart devices: Cat5e or Cat6. Smart TVs and console gaming both fit comfortably inside 1 Gbps.
- Garage with EV charger and security camera: Cat6 minimum. EV chargers tolerate electromagnetic interference poorly; cameras want reliable continuous upload.
- Mesh-node satellite backhaul: Cat6 for any current consumer mesh. Cat6a if the mesh node is Wi-Fi 7 with 2.5 GbE or 10 GbE ports.
The pattern: Cat6 is the home-network floor in 2026. Cat6a is the future-proof option. Cat5e is acceptable for short, low-bandwidth runs you're not going to redo. Anything else is either marketing or commercial-grade overkill for a residence.
When the cable is the problem
If you suspect a specific cable has degraded — particularly if a wired device suddenly caps at exactly 90 Mbps — the typical cause is one or more of the four pairs in the cable failing the auto-negotiation handshake. Replace the cable first; that's a five-minute test that resolves most cases.
For sibling reading, the cabling-vs-alternatives debate continues in MoCA vs running ethernet — when the right answer is to use the coax that's already in your walls instead of running new cable.