How-To Geek
How to Find The Best Wi-Fi Channel For Your Router on Any Operating System

Choosing the best Wi-Fi channel on your router helps to reduce interference and improve your WI-Fi signal. These tools will help you identify the least congested Wi-Fi channel in your area.
Wi-Fi channels overlap with nearby channels. Channels 1, 6, and 11 are the most frequently used for 2.4 GHz Wi-Fi. These three channels are the only ones that don’t overlap with each other.
Android – Wifi Analyzer
The easiest-to-use application we’ve found for this is Wifi Analyzer on Android. Just install the free app from Google Play and launch it. You’ll see an overview of the wireless networks in your area and which channels they’re using.
Tap the View menu and select Channel rating. The app will display a list of Wi-Fi channels and a star rating — the one with the most stars in the best. The app will actually tell you which Wi-Fi channels are better for your Wi-Fi network, so you can go straight to your router’s web interface and choose the ideal one.

iOS – Jailbreakers Only
This isn’t possible on iPhones and iPads. Apple restricts apps from accessing this Wi-Fi data directly from the hardware, so you can’t get an app like Android’s Wifi Analyzer on Apple’s App Store.
If you jailbreak, you can install an app like WiFi Explorer or WiFiFoFum from Cydia to get this functionality on your iPhone or iPad. These tools moved to Cydia after Apple booted them from the official App Store.
You probably wouldn’t want to go through the trouble of jailbreaking just for this, so use one of the other tools here instead.
Windows – NirSoft WifiInfoView
We previously recommended inSSIDer for this on Windows, but it’s become paid software. You probably don’t want to pay $20 just to figure out which Wi-Fi channel is ideal, so use a free tool instead.
Xirrus Wi-Fi Inspector is very powerful, but it’s a bit overkill for this. We liked NIrSoft’s WifiInfoView instead — its simple interface does the job and it doesn’t need any installation. Launch the tool, locate the Channel header, and click it to sort by Wi-Fi channel. Here, we can see that channel 6 looks a bit cluttered — we might want to switch to channel 1 instead.

Linux – The iwlist Command
You could use a graphical app like Wifi Radar for this on Linux, but you’d have to install it first. Instead, you might as well just use the terminal. The command here is installed by default on Ubuntu and other popular Linux distributions, so it’s the fastest method. Don’t fear the terminal!
Open a Terminal and run the following command:
sudo iwlist wlan0 scan | grep \(Channel
Read the output of the command to see which channels are the most congested and make your decision. In the screenshot below, channel 1 looks the least congested.

Mac OS X – Wireless Diagnostics
Mac OS X actually has this feature integrated. To access it, hold the Option key and click the Wi-Fi icon on the menu bar at the top of your screen. Select “Open Wireless Diagnostics.”

Ignore the wizard that appears. Instead, click the Window menu and select Utilities.
Select the Wi-Fi Scan tab and click Scan Now. The “Best 2.4 GHz Channels” and “Best 5 GHz” Channels” fields will recommend the ideal Wi-Fi channels you should be using on your router.

How to Change Your Router’s Wi-Fi Channel
Actually changing your router’s Wi-Fi channel should be simple. First, log into your router’s web interface in your web browser. Click over to the Wi-Fi settings page, locate the “Wi-Fi Channel” option, and choose your new Wi-Fi channel. This option may be on some sort of “Advanced Settings” page, too.

If there are too many other nearby networks interfering with your signal, try getting a router that supports 5 GHz — you’ll need devices that support 5 GHz, too. However, you can get “dual band” routers that have both 2.4 GHz and 5 GHz radios for maximum compatibility. 5 GHz Wi-Fi channels are farther apart and won’t interfere with each other as much.
Excellent information. I'd like to add a little change on OS X Yosemite (at least on the Beta). When you launch the Wireless Diagnostics as you mention, there is no Utilities option in the Window menu; instead you have a choice of many screens, and the one that will provide the information and screen you mention, is the "Scan" screen (Command-4). Actually, I just looked on another Mac running OS X 10.9.5 and it behaves the same as Yosemite.
Thanks for the article and info!
Don't most routers automagically select the least congested channel?
They can, @adiamond1978, but there are some things that the router may not do properly. The most important thing you can do is set your router to only channels 1, 6, or 11. Never use channels 2-5 or channels 7-10, since those overlap other channels.
http://www.dslreports.com/faq/14250
The problem is that frequency assignments on 2.4GHz 802.11 networks are 5 MHz wide, but 802.11G actually uses a 20 MHz wide chunk. So it overlaps 5 different channels on the band. By using the two edges and the middle, you eliminate overlap and reduce the amount of interference with other WiFi networks.
Of course, there's another issue with letting your router pick a channel automatically: your router is not at the same location as your laptop (or your smartphone, tablet, video game console, or streaming box.) Remember that both the router and your laptop are transmitting and receiving radio signals, and so your laptop may be interfering with or subject to interference from a wireless source that your router can't detect. If you let your router pick a channel, it may pick the same one your neighbor is using, because your router may not be hearing your neighbor's signal, but your laptop is.
So you should really never use the automatic channel setting. Use something like WiFi Analyzer at the location you'll be regularly using your laptop or other client device. Use at your router's location, too, and then pick the channel that has the fewest strong signals at both locations. You should be looking for your own signal strength to be above -50 and for everyone else's to be below -90, if possible.
On that note: RF energy is measured in dBm, which is based on 1 milliwatt. 0dBm is 1 millwatt of power, so the numbers you will see for receivers are negative numbers. -60 is a stronger signal than -90, and the minimum useful signal for a WiFi receiver is somewhere above -90dBm.
-- http://www.metageek.net/forums/showthread.php?3245-What-is-considered-a-usable-signal-strength
So you can see that the Mikeandcath network in this example is going to be virtually unusable by @ChrisHoffman, but the DIRECT roku network is strong enough to get in his way. So he should choose channel 1, where the only competitor is the yellow TELUS network.
I understand why 1 and 11 are better, but why 6?
If you transmit on channel 1, you're actually transmitting 2 channels below 1: let's call those -1 and 0. You're also using channels 1, 2, and 3.
When you transmit on 11, you are actually using channels 9,10, 11, 12, and 13.
So that leaves channels 4, 5, 6, 7, and 8 open. If you transmit on channel 6, you're occupying channels 4-8.
Wow, great follow up reply, thanks for the info!
You're very welcome. I do ham radio... You learn a lot about this kind of stuff when you study for your license and build your own equipment.![:smile: smile]()
At least our WLAN-armed modems have feature to auto-select channel, and we're happy with it; though, the area where the WLAN needs to be is fully covered by its smallness.
Netstumbler (http://www.netstumbler.com/downloads/) is a great tool for Windows too like as InSSIder and it is free.