The world is a global village and communication with family, friends, loved ones, business, clients etc. is just a click or a phone call away. In order to connect to these people or services, we need to connect to a network or the internet. This can be frustrating sometimes especially when we are in areas where there is very little to no connection or the signal strength is poor. So, would you like to learn how to check signal strength on your smartphone? Well read on.

(image credit: Dreamstime on Pinterest)

In the third world, especially in a place like Nigeria, the services (calls and internet) provided by different providers are volatile. Hence a lot of people have at least three sim cards from the different network providers just to be safe. It is very painful to spend your hard earned money on data from one provider, only for that provider to be unable to provide you internet service. This happens a lot.

So before buying data or airtime (for calls), most people would like to know how to check which provider has the best signal strength in an area before choosing to spend their cash. So, if there are several network providers in the area, and you wanted to choose the one with the strongest connection, here is how to check the signal strength on your smartphone for each of them.

Read: What are network modems on your Smartphone?


Like most people, I used to check the bars at the top of my screen to gauge the network reception but I found out that they do not mean jack shit. The signal strength received by a phone is measured in decibels (dBm). dBm is measured alongside the Asu (arbitrary strength unit).

Decibels (dBm):

For 3G networks

-40 to -50 (Excellent, you are close to a network tower)

-50 to -60 (Very good connection strength)

-60 to -70 (Good)

-70 to -80 (ok)

-80 to -90 (poor)

-90 to -110 (weak)

More than -110 (unusable or no signal)

For 4G networks

-50 to -90 dBm (Excellent)

-91 to -105 dBm (Good)

-106 to -110 dBm (Fair)

-111 to -119 dBm (Poor)

-120 dBm and above (Dead zone)

Arbitrary strength unit (Asu)

This is a value that can be used to measure signal strength as well. Its value is proportional to the signal strength and can actually be converted into decibels using this very simple formula (only works for 3G networks).

dBm = -113 + (2 x Asu)

An Asu can range from 0 to 97. The higher the number, the better the signal.

(A screenshot from my phone showing signal strength)

In the photo above, we have a dbm of -89 and an ASU of 12. We can convert the dBm to Asu and vice versa, using the formula above.

To convert Asu into dBm
dBm = -113 + (2 x Asu)
dBm = -113 + (2 x 12) (remember that Asu is 12 in the screenshot)
dBm = -113 + (24)
dBm = -89

To convert dBm into Asu
dBm = -113 + (2 x Asu)
-89 = -113 + (2 x Asu) (remember that dBm is -89 in the screenshot above)
-89 = -113 + 2Asu (collect like terms)
-89 + 113 = 2Asu
24 = 2Asu (divide both sides by 2)
Asu = 12


On androids, it is very easy, simply enter settings, scroll to about phone and click on it, the enter status and check for signal strength.

On iPhones however, Apple made it a little difficult so you may have to get on the apple store to look for an app that can help you with that or

  1. Go into your Settings / WiFi / Turn Off WiFi.
  2. Check your iOS and:
    1. For iOS 11 and later go to Settings / Cellular / Cellular Data Options / Enable LTE / Turn Off LTE.
  3. Make a phone call to *3001#12345#* and press call.
  4. Select Serving Cell Measurements and refer to the top item named Measured RSSI.

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