How to choose the best Wi-Fi channel (2.4, 5 and 6 GHz)
Why your Wi-Fi slows down when the neighbours' networks share its channel, which channels never overlap, and how to measure your own air before you change anything on the router.
Why the channel matters
Every Wi-Fi network talks on a slice of radio called a channel. Two networks on the same slice do not crash into each other: they take turns, like two conversations in one room. Each waits for the other to finish, and both get slower. Two networks on slices that partly overlap are worse — they do not hear each other well enough to take turns, so they simply talk over one another and both have to repeat what was lost.
That is why the same router can feel fast at noon and sluggish at nine in the evening: the flats around you switch on their TVs, consoles and laptops, and the air on your channel fills up. Moving to a quieter channel costs nothing and is often the single biggest improvement you can make without buying anything.
2.4 GHz: only three channels that never overlap
The 2.4 GHz band has 13 channels in Europe (11 in North America), but they are only 5 MHz apart while each network is 20 MHz wide. Channel 3 overlaps channels 1 to 5; channel 8 overlaps 6 to 10. The only set that never overlaps is 1, 6 and 11.
So the rule for 2.4 GHz is short:
- Use 1, 6 or 11, never anything in between. Sitting on channel 3 between a neighbour on 1 and one on 6 gets you the interference of both and the turn-taking of neither.
- Sharing channel 6 with a neighbour is better than sitting next to it on 7.
- Keep the width at 20 MHz. A 40 MHz network on 2.4 GHz takes up two thirds of the band and collides with everything around it.
2.4 GHz reaches further and goes through walls better, which is why smart plugs, cameras and older devices still use it. It is also where microwave ovens, Bluetooth and baby monitors live, and no Wi-Fi app can see those.
5 GHz: plenty of room, with one catch
5 GHz has many more channels that do not overlap, so finding a quiet one is usually easy. They come in groups:
| Channels | What to know |
|---|---|
| 36–48 | Always available, the usual default. Often crowded for exactly that reason. |
| 52–144 (DFS) | Shared with weather and aviation radar. The router must listen for radar for about a minute before using one, and leave it if radar appears. Usually the quietest channels in a city. |
| 149–165 | Allowed in some countries, restricted or low-power in others; check what your router offers. |
Width is a trade-off here too. 80 MHz is the sweet spot for most homes and offices: fast, and still leaves room for neighbours. 160 MHz doubles the peak speed only if the air is empty, and in a block of flats it rarely is.
If a device drops off for a minute now and then on a DFS channel, the router may be detecting radar and moving. Pick a channel in 36–48 instead.
6 GHz: the empty motorway
Wi-Fi 6E and Wi-Fi 7 routers add a 6 GHz band with dozens of clean channels and, so far, very few neighbours. If both your router and your devices support it, it is the fastest and calmest option — at shorter range than 5 GHz. Older phones and laptops cannot see it at all, so keep 5 GHz running alongside.
Measure before you change anything
The router’s “automatic” channel picks something when it starts and often never looks again. Before choosing by hand, look at the air where you actually use the Wi-Fi, at the time it feels slow:
- Scan from the right place. The desk, the sofa, the meeting room — not next to the router, where your own network drowns everything else.
- Count the neighbours, and weigh them by signal. A network at −85 dBm barely matters; one at −60 dBm on your channel matters a lot.
- Pick the quietest of 1, 6 and 11 on 2.4 GHz, and the quietest group on 5 GHz.
- Set it in the router (usually under Wireless → Channel), switching off automatic selection for that band.
- Test before and after. Run the same speed test, from the same spot, at the same time of day.
- Look again in a few weeks. Neighbours change routers and channels too.
How to scan, device by device
- Android: a Wi-Fi analyzer app can list every nearby network with its channel and signal. Android allows an app four scans every two minutes, so a fresh reading can take a moment.
- iPhone: iOS does not let apps list nearby networks. Apple’s own AirPort Utility has a Wi-Fi scanner you can switch on in Settings → AirPort Utility.
- Windows: open a terminal and run
netsh wlan show networks mode=bssid— each network is listed with its channel and signal. - Mac: hold Option, click the Wi-Fi icon, choose Open Wireless Diagnostics, then Window → Scan.
Doing it with NetBlade
NetBlade for Android has a Wi-Fi analyzer that does the measuring for you, free and without an account:
- a channel graph for 2.4 and 5 GHz, one colour per network — tap a network in the list and its curve lights up, tap a curve and the list jumps to its network;
- a channel recommendation that names the least busy channel on each band, weighting every neighbour by how strong it is and how much it overlaps, leaving your own network out of the count — and it only suggests a move when the new channel is clearly quieter, otherwise it tells you yours is already the right one;
- a history of past scans, so you can compare Monday evening with Saturday morning before you settle on a channel.
Scan, change the channel in the router, scan again: the graph shows whether you really moved away from the crowd.