How do cell phone bars actually measure performance?

We’ve all been there: you’ve got one lonely signal bar just loitering at the top of your phone screen when your friend standing right next to you has full bars. Why does this happen? This article will dive into what those cell phone bars actually indicate and what they do (and don’t) mean when it comes to your phone’s performance. 

What do the bars on my phone mean?

Cell phone bars are a signal indicator, reflecting the strength of the radio signal your phone is receiving from a nearby cell tower. More bars usually means a more stable connection, but it doesn’t necessarily mean faster data speeds or better call quality. 

There is also no industry standard for how a cell phone’s bars correlate to signal strength. Each phone manufacturer sets its own levels, so signal bars can vary between phone models, even when they’re on the same network. And if your phone moves closer to another tower or switches from 4G LTE to 5G, the number of bars may change even if you don’t notice a difference in your service quality.

Cell phone bars: Myths and misconceptions

• More bars = better performance
  • This is a common misconception. Bars are merely an indicator of signal strength. You may get full bars while at a sold out concert or a packed sports event, but if everyone around you is using their data at the same time, that could bog down the network and slow your service. On the flip side, you could get only two or three bars while in a rural area but if you’re one of only a few people connected to that tower, your performance might still be top notch. 
• If you got full bars in a place before, you’ll always get full bars there
  • Just because you had a strong signal at one location previously doesn’t mean that will always be the case. Environmental changes like new buildings, or any nearby towers being moved/decommissioned could affect your signal in that location going forward.
• If my last phone got full bars somewhere, my new phone should too
  • The way signal bars are measured vary by phone make & model, so what one phone model considers to be a three bar signal, another may consider to be only a two. Also, factors like the placement of the antenna or a new phone case could have an impact on the signal strength.  

So how is cell phone signal strength actually measured?

Signal strength is technically measured in dBm, which stands for decibel-milliwatts. It’s a unit of power that is shown as a negative number on your phone, and the closer to zero it is, the stronger your signal. Typically, about -55 dBm is considered an excellent signal, while -85 dBm is a strong signal while indoors (but performance may vary). Once it falls below -100, that’s considered a weak signal.

Now that most phones operate on LTE or 5G networks, there are two other measurements that come into play: RSRP (Reference Signal Received Power) which measures signal strength, and RSRQ (Reference Signal Received Quality) which measures the quality of the signal relative to interference. Think of the network like a speaker playing music. You have a stronger “signal” to your speaker standing right in front of it than someone standing in the other room, so you can hear the music better. But if there’s a bookshelf between you and the speaker, or you’re wearing something over your ears, that would affect your signal quality.

How to check signal strength on iPhone & Android

Now that you know what dBm and RSRP mean, you can use the Field Test feature on your phone for a precise reading of your signal. 

How to check signal strength on iPhone

1. Make sure Wi-Fi is turned off via Control Center or Settings
2. Open the Phone app and go into the Keypad
3. Dial *3001#12345#* and press the Call button
4. When the info pops up, look for RSRP or RSRP0 where it displays your LTE/5G metrics

How to check signal strength on Android phones

1. Go into Settings and make sure Wi-Fi is turned off
2. While there, tap About Phone
3. Select Status Information or Network
4. Tap SIM Card Status
5. There should be a field labeled Signal Strength, and your dBm will be displayed there

Clear signal, full bars, can’t lose

That’s the full download on what signal bars really mean. If you’ve got a quality signal right now and want to keep learning about your phone, you can check out our other articles about airplane mode (a feature that will knock out those bars entirely) or educate yourself on the history of iPhone, Android or just phone numbers in general. And if you’re looking for a good signal with a side of great savings, consider bringing that phone to Mint Mobile, where you can get unlimited talk & text and 5G data on America’s largest 5G network. Click below to see why Mint is the best choice for people who want to keep their bars and their money.