How Accurate Are The Bars On Your Phone?

Are they the best way to determine the strength of your cellular signal?

Everyone assumes that the number of bars on our smartphones is an accurate reading of the strength of our cellular signal. But is it?

While they do indicate signal strength, it’s up to the smartphone manufacturer to use whatever algorithm they want to measure that strength. There is no standard unit of measurement for a cell phone’s bars. So while one phone is showing 2-3 bars another carrier’s phone could be showing 4-5 bars.

Cellphone manufacturers don’t think in terms of bars, they think in terms of signal to noise ratio. Simply put, this means that with today’s crowded airwaves people around you making and receiving calls represent noise to your phone that can interfere with your reception. Your phone is constantly measuring the airwaves around you and based on its results it uses it’s own particular formula to create a moving average of the activity around you that it then applies to a 1 to 5 bar scale.

So if you’re in a crowded place, with multiple cell phone users, and you could be connected to the same cell tower as the guy next to you, but based on your cell phone’s manufacturer there’s no guarantee you’ll have the same number of bars on your screen.

Do more bars mean you have a stronger signal?

Usually the answer is yes, but in some cases you may have interference or capacity problems and while it appears you have 3 or 4 bars of signal, your service may still be unreliable.

How often do the number of bars change?

Depending on the type of phone you have, updates may not run very often. It sometimes takes up to 15 minutes to reset.

Think of all the times you may have walked around, looking at those bars, expecting to see a change, you may have been wasting your time.

Getting an Accurate Signal Reading

The only true measure of signal strength is to put your cell phone into field test mode. This is a menu on most cellphones that provides cellular signal readings information. The code to access it varies from device to device.

Cellular signals are measured in decibels and usually appear as a negative number (for example -85). A good signal is between -70 and -90dB. A very strong signal would be -50dB.

How to Find Field Test Modes:


Dial in *3001#12345#* and hit “Call” and you’ll get the field test screen and in the upper left hand corner your dB reading will appear instead of bars.

Android Devices:

Download an application such as Network Signal Info.

Another Solution:

No reception, no problem! SureCall carries a line of award-winning cellular signal boosters that provide clear and consistent cellular reception for all carriers to any location including buildings, homes, vehicles and watercraft that cover areas as small as the front seat of your car, up to 250,000 square feet.


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