Wi-Fi vs. ethernet: how much speed are you losing?
The most common "slow internet" complaint in any home has nothing to do with the internet. The fiber delivers 500 Mbit/s to the router — and the router delivers 60 to your sofa. The gap is the radio path, and it's bigger than most people suspect.
The numbers on the box are laboratory fiction
Wi-Fi standards advertise their theoretical maximum: a lab figure measured a meter from the router with zero interference and no other devices. Real homes don't look like that. As working rules of thumb:
| Situation | What you typically get |
|---|---|
| Ethernet cable | 100% of the port speed, constantly |
| Wi-Fi, same room as router | 50–70% of what a cable would deliver |
| Wi-Fi, one wall / one floor away | 25–50% |
| Wi-Fi, two+ walls, far corner of the home | 10–30% — and unstable |
Concrete/brick walls, underfloor heating, mirrors, and aquariums are notorious signal killers; a metal-backed TV mounted between the router and the sofa can do surprising damage on its own.
It's not just speed — it's steadiness
The subtler difference is latency and its consistency:
- Ethernet: ~0.1–0.3 ms added, essentially zero variation, no packet loss.
- Wi-Fi: 2–10 ms added on a good day — but with spikes of 50–200 ms when interference hits, plus occasional lost packets that must be re-sent.
Big downloads don't care about spikes. But video calls freeze on them, game inputs stutter on them, and web pages hesitate on them. If your calls glitch while speed tests look fine, you're seeing Wi-Fi jitter, not slow internet. (Latency also dominates how "fast" browsing feels — explained in what's a good speed.)
Two bands, one classic mistake
Your router broadcasts on two (or three) radio bands, and being on the wrong one is the most common self-inflicted slowdown:
- 2.4 GHz: long range, punches through walls — but slow (real-world often 30–80 Mbit/s) and crowded: only 3 non-overlapping channels shared with every neighbor, plus microwaves and baby monitors.
- 5 GHz (and 6 GHz on newer gear): several times faster, many more channels, far less interference — but shorter range and weaker through walls.
Devices sometimes cling stubbornly to the 2.4 GHz band even when 5 GHz is available. If your router broadcasts them as separate network names, connecting important devices explicitly to the 5 GHz one can triple their speed with zero money spent.
Cable what matters, Wi-Fi the rest
Nobody cables a phone. The winning setup is selective:
- Worth a cable: the TV/streaming box (it never moves), a gaming PC or console (kills the jitter problem entirely), a desktop used for video calls, anything doing large uploads.
- Fine on Wi-Fi: phones, tablets, laptops that move around — that's the point of them.
- No ethernet ports in the walls? A mesh system with a wired or dedicated wireless backhaul beats a single router shouting through three walls. Cheap Wi-Fi "repeaters" halve throughput by design — they receive and re-send on the same radio — so treat them as a last resort.
Run the 10-second test →
The five-minute diagnosis
- Speed test next to the router. This is your baseline — roughly what your provider delivers.
- Same test where things feel slow. The gap between the two is pure Wi-Fi loss.
- Gap small but everything still slow? Then it's not Wi-Fi — it's the line or the site: work out which.
- Gap huge? Try the 5 GHz band, move the router out of the closet (up high, central, in the open), and cable the one device that suffers most.