It isn't quite as simple as changing channel on your TV but you can change the channel your router uses for Wi-Fi in order to avoid interference from neighbouring networks.
Although you may know that your router uses 2.4GHz for 802.11n and 5GHz for 802.11ac and 802.11n, you might not realise that there's a choice of 'channel' on each frequency. Essentially, routers can pick from quite a few different channels and many choose this upon initial setup based on which other networks are broadcasting in the local area.
The best Wi-Fi channel, therefore, is one that isn't being used by all your neighbours. By manually switching to a less-crowded channel, or one currently not used by any other networks, your Wi-Fi should improve markedly. We'll show you how to identify which channels are most crowded and how to change channel on your router.
When your neighbours change their router, yours probably sticks with the default channel or the one it chose when you first set it up and this is why your Wi-Fi can be fine one day, and terrible the next. Some routers, notably BT's Home Hubs, can change their channel to avoid interference, but you may still prefer to use the technique below to see if there's a better channel with less interference.
When multiple Wi-Fi networks overlap, it can cause so much interference that you'll all suffer from slow Wi-Fi speeds which means web pages will take longer to load and videos might stutter when streaming from YouTube or iPlayer.
The problem could lie elsewhere. If it's poor Wi-Fi coverage causing the problem, it could be fixed by buying a mesh Wi-Fi kit - such as the excellent Linksys Velop Dual Band - but if you can see your device has a strong Wi-Fi signal, slow speeds can be due to interference.
Which is the best Wi-Fi channel?
The best one will be different for everyone. You need to discover which channels nearby networks are using, and you can do this with a free app. We're using an Android tablet here and the free WiFi Analyzer app. It's also available for Windows 10.
There isn't a direct equivalent for iOS, and apps in Apple's App Store aren't allowed to report signal strength either, so it's best to use Android or Windows apps.
Start by ensuring your phone or tablet is connected to your Wi-Fi network (as opposed to 3G or 4G) and then open the app. If your router has separate networks for 2.4GHz and 5GHz connect to each in turn and check whether one or other is less crowded.
You'll see a graph that shows the nearby Wi-Fi networks separated by different colours. You can also see the channels they are currently using along with the strength of signal (a higher curve is a stronger signal). This will give you an idea of whether your network has a strong or weak signal and whether the channel is currently set to is crowded or not. This will help you decide which channel you need to use. It's worth noting that out of 13 channels, all but 1, 6 and 11 overlap. So pick a channel as far away from your neighbours' if possible.
It's the vertex (highest point) of the parabola which tells you which channel it is using. In the example above you can see the 2.4GHz frequency is very crowded and there is no obvious 'best' channel number. Our network is set to channel 6 and has the strongest signal, but three other networks still overlap it.
On routers which also support 5GHz, it's worth connecting your phone or tablet to that network to see if it's less crowded. Some routers have two separate network names which makes it easy to identify which is which, but others broadcast a single name and your phone decides to which network to connect (but you won't be able to control this).
If possible, look for a setting in your router's Wi-Fi options (see below) to check if you can force it to display the 2.4GHz and 5GHz networks separately so you can manually connect to the 5GHz one.
Both your router and your phone must support 5GHz Wi-Fi for this to work. It's often called 'dual-band' Wi-Fi in the specifications list rather than 5GHz, though.
If you want to stop your phone or other devices (such as your laptop) automatically connecting to your router's 2.4GHz Wi-Fi and only use 5GHz, you'll need to figure out how to 'Forget this network' on your particular device.
After that, it should only connect to the 5GHz network.
How do I change Wi-Fi channel?
You need to access your router's web interface. This can be done by opening a web browser and typing in the router's IP address. This number will either be printed in your router's documentation or possibly on the bottom of the device itself.
If not, open a Command Prompt in Windows (PowerShell in later versions) and type 'ipconfig' without the quotes. Now look through the resulting text for the default gateway address. This is your router's IP address, and will be similar to 192.168.1.1. For more help see our guide on how to connect to your router.
Using this default gateway address, type it into the search bar in your browser and your router's admin page should be displayed.
Next you'll be asked to enter a password (possibly a username too) and, again, it will either be printed on the router itself, on a sticker or card that came with it, or in the manual. Ideally, you should change the default password to prevent anyone else accessing the settings.
From the web page that is displayed, look for the Wi-Fi settings. The channel number should be selectable via a drop-down menu. Note that if your router does work on 2.4GHz and 5GHz, you will have to choose the channel separately for each.
The exact location of the option will differ depending on the router manufacturer. In this instance, we used a D-Link router and the channel settings were found by clicking Advanced from the main page. We then selected Wireless setup from the options on the let-hand menu and then chose Manual Wireless Network Setup.
Make sure you save the settings - your router may reboot to apply the change.
Hopefully this will fix your problem, but in places, such as a block of flats where there are lots of networks in close proximity, you might struggle to find a better channel.