See The Actual Signal Strength On Your iPhone With This Quick Tweak

iPhone: Ever feel tricked by your iPhone's signal bars into thinking you have a better reception that you actually do? This simple hack will turn those bars to show the actual signal in decibals (dBm). No jailbreaking is required and it's reversible.

Here are the instructions from Redmond Pie:

Step 1: Dial *3001#12345#* on your iPhone then press Call.

Step 2: You'll now enter Field Test mode. You'll notice a signal strength indicator on the upper left hand corner of your screen. You can toggle between signal strength bars and a number by simply taping on it. At this point, press the home button to exit the app or if you would like the feature to be permanent, continue on. Don't worry, the process is completely reversible.

Step 3: Hold down on the Power button until you see the "slide to power off" bar. Do not power off the device.

Step 4: Press down on the Home button until the app closes and you return to your home screen.

That's it. Even when restarting the iPhone, the signal strength can be toggled between bars and numbers. The closer your number is to zero, the stronger your signal is.

The lower your number, the stronger your signal — but don't include the - sign when evaluating (so, if the signal says -60, that's better than -90).

To return to the default bars permanently, follow these steps:

Step 1: Dial *3001#12345#* on your iPhone then press Call.

Step 2: Press on your Home Button once.

This trick may come in handy when you're in a dead zone and need to know where to move to for a better signal. (If you're constantly suffering from poor signal woes, try boosting your signal with a drinking glass or a cheap bracelet.)

By the way, Android users can take a look at their dBm number under Settings > About Phone (it may be under Network or Status, depending on your phone).

How Strong Is Your iPhone Signal? Find Out Now! [No Jailbreak Required] [Redmond Pie via Neowin]


    Doesn't work on Vodafone. Message appears: "Error performing request. No network service. Bummer.

      I'm on vodafone and it didn't work for me either with the same message you got. But then I realised there is an asterix after the hash at the end and now it works.

    Awesome! I never knew about this and it's a great way to quantify how crap my reception is.
    Does anyone know why is isn't a widely accessible feature in iOS?

      because then people would be able to compare iphones reception to other makes, and discover if it's actually shit. If they use their own indicators, people believe its amazing.

        And yet my iPhone 4S always has better reception than my GS3 (Both Telstra), Sometimes it's 1-2 bars, sometimes the difference is 3G or no.

        *Waits for Tim's accusation of fanboyism*

          not making any claims of who's reception is better than who's. Also not claiming that other manufacturers dont fudge the numbers in their own signal reception display. Also, '1 or 2 bars better' is exactly the kind of display that can be misleading, if the samsung is accurately displaying signal strength, and 4s is using its own scale to look good. As this article was about the iphone, it's relevant to comment about the iphone, as there was discussion when it was released that the numbers were adjusted to make it's reception look stronger than it was.

          Have fun with your device(s)

    but don’t EXCLUDE the – sign when evaluating

      No, don't INCLUDE the minus sign when evaluating. As they said, the lower the number is (EXCLUDING the minus symbol) the better the reception.

    Works on Voda for me

    Checking info within this field test app I see that the transmit streanghth is 128, so I'd assume the scale is from -128 to 0

    -78, but I am in an concrete building.

    That is a fantastic tip. I am sick of seeing full bars on the phone and my data connection is crap.

      Crap data connection is due to overloaded network, when lots of people are using it at once.

    Is there anyway to do this on an iPad?


      1) Turn on multitasking gestures in the settings menu.
      2) Quit all apps.
      3) Open up Safari.
      4) Use the 5-finger-scroll gesture to scroll to the left.

      Now you'll be at the same Field Test Mode screen as you'd see on the iPhone.

      To make it permanent, try following steps 3 and 4 from the main article.

      Last edited 16/12/12 2:09 pm

    I like how they have to explain how negative numbers work.

      Yeah I was just about to make the same comment. Obviously -90 is worse than -60.... -.-

    No joy on Optus. 'Error performing request. No network service'. Has anyone in the LH office tried is on an AU network?

    Actually, scratch that. I missed the final * at the end of the code. It indeed works. I'm in a very busy business suburb and am rating at -90. Not that good IMO!

    Some kind of graph would be interesting, to show values and how they correspond to bars...

    I'm getting -48 at the moment (we have Telstra repeaters in our building), where I usually get 4 or 5 bars. I wonder how close I'd actually have to be to a tower to get anywhere near zero...

      Approximate correlation of signal (dBm) to signal bars:

      -128 to -103 = 1 bar of reception
      -102 to -77 = 2 bars
      -76 to -51 = 3 bars
      -50 to -25 = 4 bars
      -24 to 0 = 5 bars

      Last edited 16/12/12 12:26 pm

        This is wrong. -128 is the TRANSMIT signal, and is the 5 bar equivilant.
        Ignore the minus sign you idiot.

          No, you are wrong. The nearer the signal value is to zero, the stronger the reception. Next time you call someone an idiot, try not to be a dumbshit whilst doing so.

          Last edited 16/12/12 11:01 pm

    **WARNING** I cannot sync my iPhone with iTunes after doing this!

    I have tried to fix it, but from what I've read of other forums entering Field Test Mode means you'll probably have to restore your iPhone.

    Anyone else having syncing issues???

      ...ok, false alarm, I was able to get it to sync again - but iTunes did not like the fact that my iPhone was in that pseudo-Field Test Mode. The hard reboot didn't work, but the power off seemed to ?!?!

      ....anyway, I won't be doing it again.

      this broke my phone! 24 hours after attempting this my phone crashed due to software problems! couldnt turn it on, sync, back up or restore my phone due to an "unknown error" on top of that the battery needs to be replaced. $140 down the drain to get it repaired. Be wary.

    Hi I tried to revert back to the signal bars permanently as per your instruction but unsuccessful!

    After dialing the number I press the Home Button once and all it did was go back to springboard and when I tap the signal bar, it continues to toggle to digits.

    It appears to affect my PowerAlert app (jailbroken app) and I am no longer getting the alerts that I used to.

    Please help!

    Awesome! Worked for my on my iP5 with Telstra. I just rebooted the phone to check if it's a permanent option and it's still available to toggle even after a reboot.

    If you've made this a permanent tweek, you can switch between dBm and bars by simply touching the area of your iPhone where it's displayed :)

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