How to Check Wireless Signal Strength and Optimize WiFi Networks in Mac OS X

Dec 28, 2011 - 47 Comments


Wi-Fi Diagnostics is an incredibly useful utility to troubleshoot and optimize any wireless network and the signal strength of computers that are connecting to it. This utility first came bundled in Mac OS X Lion and works with all wireless routers and not only the Apple branded ones, meaning you can improve the performance of just about any wifi network by using it and making some adjustments along the way. It’s easy to use and we’ll walk you through the process of getting the best wireless signal using the app, but first we have to uncover the tool itself.

The Wi-Fi Diagnostics app is buried within Mac OS X 10.7 & OS X 10.8, here’s how to access it:

  • From the OS X desktop, hit Command+Shift+G and enter the following path:
  • /System/Library/CoreServices/

  • Sort alphabetically and find “Wi-Fi Diagnostics”, if you plan to use the app even somewhat frequently it’s recommended to drag Wi-Fi Diagnostics into Launchpad for easy access

With Wi-Fi Diagnostics now in the easier to access Launchpad… open Wi-Fi, then:

  • For OS X Lion users, check the radiobox next to “Monitor wireless performance” then click on the “Continue” button
  • For OS X Mountain Lion (and later) users, pull down the “View” menu and choose “Performance”, or just hit Command+5

Why Apple changed the process between OS X 10.7 and 10.8 is a mystery, but the feature remains in the newest versions of Mac OS X regardless. Anyhow…

Monitor WiFi Performance

Now is when the fun begins. The chart you see is a live wireless signal strength and noise meter, you want the yellow signal strength bar to be as high as possible. Pay attention to the green line of noise as well, you want that to be as low as possible in relation to the yellow line of signal strength.

Monitor wireless signal strength

If the signal strength is high and noise is low, you’re already good and you don’t need to change much. For most of us, signal will be lower than we want it to be, depending on where the wireless router is stored in relation to our computer gear.

Here are some tips to try out and to improve signal strength, keep an eye on the signal as you make adjustments:

  • Tweak the physical antennas on the wireless router and aim them in different directions
  • Move the wireless router away from walls, fireplaces, etc – even just a foot or two of space can make a big difference
  • Move the wifi router away from TV’s, microwaves, refrigerators, and other electronics that may interfere with signal
  • Relocate the Mac in relation to the router, this is obviously easiest with a MacBook Air or Pro
  • Consider changing Wi-Fi network channels if there are many matching channels from nearby routers

Once you have arrived at a reasonable compromise to how your hardware is physically configured and the resulting signal strength, enjoy your newly optmized wifi network.

Wifi signal meter

Some important things to remember here: not all internet connections are capable of transferring data at optimum wireless speeds, so you may not notice much of a difference in internet connectivity speed if any at all with these adjustments. This basically means that a weaker wireless signal may be more than adequate to transfer data at your ISP’s maximum bandwidth. Regardless, you’ll want the noise level to be as low as possible, since large amounts of wifi network noise can result in lost packets, reduced speeds, quirky behavior, random wireless connection dropping, and a variety of other problems.

If a wireless network is configured well and you continue to have problems with connectivity, check out some of our past articles on resolving such issues:

Using Wi-Fi Diagnostics I discovered my wireless signal to be much weaker when keeping the wifi router out of sight behind an LCD TV, simply moving the router away from the TV a few feet dramatically boosted signal strength. Run the app yourself and see what kind of performance boost you can get by adjusting your own wifi network.


Related articles:

Posted by: AJ in Mac OS, Tips & Tricks, Troubleshooting


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  1. I know others have said this, but in March 2023, Venture, option click on the wireless symbol in the menu bar allows access to the Wireless Diagnostics app and the the Window menu there gives a range of tools, scanners and sniffers.

    I found it helpful as a quick alternative to iStumbler, with its recommendations for best bands for 2.4 and5 GHz settings in my router.

  2. Riccardo says:

    I don’t know if anyone else already posted this, but another way to access the Wireless Diagnostics in OSX El Capitan is by hold down the Option key and then click on the Wireless menu item to reveal the “Open Wireless Diagnostics…” hidden menu item

  3. Phil says:

    Really useful article! Helped me so much.
    In El Capitan this utility located in

    It opens great window and on summary page you will see best channel for each band (like Best 2.4 GHz: 1,2).
    If you can, choose a channel, which is not surrounded by other busy channels or a least one free from one side.
    The best way to figure out the perfect channel is to use Visual Spectrum Analyzer but that stuff really hard to find for that band.

  4. BambiB says:

    The useful real-time tools seemed to have been replaced by a “report generating” tool that spews out megabytes of far less useful data and provides a very limited “monitoring” function (that basically just tells you if your WiFi dies… and little else.)

    Apple appears to have taken a giant step backwards in WiFi diagnostic utility.


  5. Perry says:

    Now called “Wireless Diagnostics” in the Applications sub-folder (El Capitan release)

  6. jason says:

    This information is mostly out of date.

  7. Dipesh Timilsina says:

    I am using MacBook Air 2014 with Yosemite installed. I can’t see to find the Wi-Fi Diagnostics Utility at all. My internet is running all fine but the reception is very poor which is very strange.
    How can I diagnose this?

  8. Salomon says:

    Please note, as of OS X Mavericks, the Wi-Fi Diagnostics utility is renamed to Wireless Diagnostics and can be found in this path /System/Library/CoreServices/Applications

  9. […] can be helpful when resolving problems with internet connectivity when a wi-fi connection has been determined to be stable, or when a machine on the network can’t access the outside world after power-cycling a […]

  10. Glenn says:

    My yellow line has these occasional drastic dips…which jibes with the problem I was trying to solve, which is that my wifi seems suddenly to turn to mud (usually in the middle of an online game when speed is important). Any hints?

  11. Mantas says:

    its easier to hold option key and then click on Wi-Fi icon in task bar :)

  12. […] DHCP and MTU fix), a problem the router itself, or something as simple as network interference (here’s how to check connection strength and interference issues), which can often be resolved by reconfiguring a routers physical arrangement or changing […]

  13. […] Wi-Fi Diagnostics app is also in OS X Lion, but the Option+Click shortcut does not work to launch it, and the Lion version does not include […]

  14. […] already powerful Wi-Fi Diagnostics Tool in Mac OS X got a redesign in Mountain Lion and with it came some new features that make it better than ever. […]

  15. Alan says:

    For those who still read this article after the release of Mountain Lion, Wi-Fi Diagnostics has changed in Mountain Lion. It’s now just a report generating tool – could not find any option to Monitor Performance as described in the article.

    I copied the app from a Mac still running Lion, and copied it to my Utilities folder on my Mountain Lion MBP. Works just fine.

    Save the newly copied app in a backup folder for all the apps you collect so you don’t lose it. Or, back up the app into some other folder, such as a backup folder, before running the Mountain Lion install.

    • Prasad says:

      While report generating window is what opens on launching wifi diagnostics, you will under tools network utilities including ‘monitor performance’

      • mini says:

        In ML:
        File->Network Utilities->Performance



        • BOTRO says:

          The first time I ran this the “Monitor” Performance screen came up. But not after the first time. And under the View menu it has “Performance” not “Monitor performance” and the Performance window looks different than the screen capture above. Why did this change after the first time running it?

  16. […] shown as the signal, the better the connection, just like measuring wireless signals in the hidden awesome OS X Wi-Fi tool. For example, -20 is a much stronger signal than -90, but don’t feel bad if you can’t […]

  17. […] How to Check Wireless Signal Strength and Optimize WiFi Networks in Mac OS X Lion […]

  18. […] you’re a perfectionist, you could then run the Wi-Fi Diagnostics tool and get the optimal signal for the network, but in a brief hotel or airport situation, the the […]

  19. Wayne Neale says:

    Great tool! Thanks. Here’s an odd one, having opened this app.

    My brand new 27 inch iMac in the UK shows FR as the country code in the diagnostic report. How did that happen, and can I somehow change this to the UK?

    Maybe connected, but my Mac cannot automatically find my location.

    • Ty says:

      Confirm your region settings, go to System Preferences > Language & Text > Formats and select United Kingdom

      • Wayne Neale says:

        Thanks, but I don’t believe this impacts on the country code of the wifi in the iMac. It was actually already set as UK in the language & text settings, but the wifi diagnostics tool tells me the country is FR. Presumably France.

        Odd! Seemingly no way to reset either.

  20. Mikey Steebers says:

    This is such a great tip but I must say I am shocked that Michael Steeber hasn’t taken this one yet??? He must be on vacation.

  21. […] How to Check Wireless Signal Strength and Optimise WiFi Networks in Mac OS X Lion […]

  22. Phil says:

    Had the same problem as Perry, solved by Naru, got what seemed like odd result, virtually straight line yellow at 50,
    virtually straight line green at bottom. Not sure if that’s good or bad, or if I need to take further steps.

  23. […] ferramentas legais para configuração e gerenciamento do serviço de diretórios. Navegando pelo OSXDaily, vi que existe essa ferramenta para monitorar redes wireless, que, por ter um ícone bem parecido […]

  24. Perry says:

    I’m running OSX Lion 10.7.2 and when I open up the launch pad there is no Wi-Fi Diagnostic app. Just to make sure I hit command+shift+G and all I get is a sound. Any help would be appreciated because my wifi needs tweaking.

    • Naru says:

      You have to enter the path into the Command+Shift+G window and drag Wi-Fi Diagnostics out of CoreServices and into Launchpad

  25. Rob says:

    @Amigalander: Make sure your computer’s Airport is turned on and connected to a signal before launching.

  26. If you use an AirPort Station (Time Capsule, Express, or Extreme), then you can check the signal strength in the AirPort Utility, too.

    This article motivated me to optimize the location of my network devices and I could improve the signal strength – so thanks!

  27. David Sucher says:

    Thx. Very helpful.

    Now I would like to know if you have any suggestions on how to optimize browser and web page loading. Periodically, they’ll just load slo-o-o-wly or even completely hang. Very annoying.

    Any suggestions in that arena?

  28. Tinman says:

    Also keep in mind that while internet access might not benefit much from tweaking wifi, local transfers can indeed benefit (copying files to/fro NAS, etc.).

  29. Tom says:

    Another Great Tip!! Thx guys!

  30. Wow this is a great tip – I didn’t know about this. Also be sure to check out NetSpot App – its the same idea but has a bit more features. via

    Thanks guys!

  31. Jas says:

    Have latest lion os, cant find the utility, how do i get to it? Info from article didnt find it, thanks

  32. Amigalander says:

    Hmm, when I run the app, the “Monitor Performance” is grayed out. So is “Capture Raw Frames.”

    I can only choose “Record Events” and “Turn on Debug Logs.”

    Any ideas?

  33. Alberto says:

    Strange, I am on the Mac Mini and I share Internet with another Mac, through wifi, but I don’t see the chart of the signal… (only the one of the noise)……

  34. Brah says:

    this is why i love OSX DAILY!! wooo

    great tip

  35. Sundaland Clouds says:

    Kickass app, this should be in the Utilities folder and not in Core Services don’t you think?

  36. Alex says:

    Glad you pointed out that a lower signal won’t necessarily effect the quality of the internet connection, because beyond 802.11g the broadband itself becomes the limiting factor. That said, higher is always better and you can always reduce noise. Regarding noise, if you have no obstructions then try switching channels on the router until you find a clear one.

    Oh and the reason you got a signal boost from moving the router away from a TV set is all that metal scatters and reflects the microwaves :]

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