Why your Wi-Fi is slow at home — and how to actually fix it

Step 1: find out whether it is the internet or the Wi-Fi

This is the test that decides everything else, and it is the one people skip. You need two numbers: the speed at the router, and the speed where the problem is.

1. Connect a laptop to the router with an Ethernet cable and run a speed test. Close everything else first.
2. Compare that to what you pay for. Within about 80% is normal; much lower means the problem is the line or the router itself, and the rest of this article will not help — call your provider.
3. Now unplug the cable, go to the slow room, and run the same test on Wi-Fi.
4. Write both numbers down. If the wired test is good and the wireless one is poor, everything below applies to you.

Step 2: router placement, where most of the speed is lost

Routers are usually installed wherever the phone socket happens to be — a hallway cupboard, behind the TV, on the floor in a corner. That is convenient for the installer and terrible for the signal, because Wi-Fi radiates outward and downward from the antennas and is absorbed by almost everything solid.

The worst offenders are water and metal. A fish tank, a boiler, a radiator, a metal shelf, a mirror or a concrete wall will each cost you far more signal than a plasterboard partition.

1. Put the router as close to the centre of the home as the wiring allows, and ideally on the floor where you use it most.
2. Raise it. On a shelf about a metre up is much better than on the floor, because the signal spreads outward and slightly down.
3. Get it out of any cupboard or cabinet, and away from the TV, the microwave and any large metal object.
4. If the antennas are external, point one vertically and one horizontally — devices receive best when their antenna is aligned with the router's.

Step 3: bands and channels, or why your neighbours are your problem

Your router broadcasts on 2.4GHz, 5GHz and, on newer models, 6GHz. 2.4GHz travels furthest and is the most crowded; 5GHz is much faster over shorter distances; 6GHz is fast and almost empty but very short range.

In a flat or a terraced house, the 2.4GHz band may have twenty networks competing for three usable channels. It is the wireless equivalent of everyone talking in one small room, and no amount of paying for faster internet changes it.

1. Use a Wi-Fi analyser app on Android, or your router's own scan, to see how many networks share your channel.
2. On 2.4GHz, set your router manually to channel 1, 6 or 11 — whichever is least crowded. Any other channel overlaps two of them.
3. On 5GHz, use the higher channels (100 and above) if your router supports them; they are typically far less used.
4. Put phones, laptops and TVs that are near the router on 5GHz, and leave 2.4GHz for the far-away and low-bandwidth things — smart plugs, sensors, a printer.

Step 4: the settings and devices that quietly cost you speed

A handful of things will slow a whole network rather than one device. Worth checking all of them once, because each takes a minute.

• One very old device can slow everything down. A laptop or printer that only supports Wi-Fi from ten years ago forces the router to spend airtime at old, slow rates. Put it on the 2.4GHz network on its own, or connect it by cable.
• Backups and cloud sync are invisible bandwidth. A phone backing up a year of video, or a computer uploading a folder, will saturate a connection completely. Check what is syncing before blaming the router.
• Old firmware genuinely matters on routers, unlike most devices. Manufacturers ship real performance and stability fixes. Check for an update — many routers do not do it automatically.
• Turn off the guest network if nobody uses it. On many routers it takes a share of airtime even when idle.

Step 5: fixing the room the signal cannot reach

If the wired speed is good, the router is well placed, and one room is still slow, you have a coverage problem rather than a speed problem. There are three real solutions and one that people buy first and regret.

The one people buy first is a cheap Wi-Fi repeater. It works by receiving and re-transmitting on the same radio, which halves the available speed, and it creates a second network name you have to switch between manually. It is better than nothing in a small gap and disappointing everywhere else.

• Mesh Wi-Fi is the right answer for most homes. Two or three units share one network name, hand devices between them automatically, and are genuinely simple to set up.
• Powerline adapters with a built-in access point are excellent when walls are thick or the rooms are far apart, because the hard part of the journey happens over the electrical wiring rather than through concrete.
• An Ethernet cable to a second access point is the fastest and most reliable option by a wide margin, and a flat cable along a skirting board is less work than people assume.
• Whichever you choose, place the second unit roughly halfway between the router and the dead zone, not inside the dead zone — it can only re-broadcast a signal it receives well.

Questions people still ask