How to Check Your Cell Phone Signal Strength

How to Check Your Cell Phone Signal Strength

Written By Alexa Mulligan
22nd Mar 2023

Bars Don’t Really Reflect Signal Strength

We worship at the altar of strong and steady bars as much as the next person. Signal strength is life! But bars aren't as trustworthy as you may think. Finding out what the bars mean on iPhone or Android may not actually be the best way to do a signal check. Luckily, there is a better way to accurately carry out a signal strength test: Use the field test mode to measure your dBm or decibels level.

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Attention business & property owners, installers and integrators

Take advantage of our system design and installation services. Learn more or call us for a free consultation: 1-800-969-8189.

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  • You are close enough to a tower for semi-good signal, but need more bars

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Buy this Cell Phone Signal Booster If:

  • You live in a small home or only need spot coverage, regardless of outside signal.
  • You need a simple installation.
  • You live in an area with lots of cell towers

The SureCall Fusion4Home is the do-it-yourself signal booster kit we recommend most for small homes and for the budget-conscious. Iys has customisable antennas to suit your situation.

For a large home, check out the Fusion5s, and click here for the full cell phone signal booster lineup from SureCall.

What Is the Difference Between Signal Strength and Signal Quality?

Signal strength is how much signal your phone router or other device is receiving.

Signal quality is how much noise or interference that signal is contending with.

Radio signals are all around us from other cell towers, other calls, other devices, or even appliances. These signals can interfere with your cell phone connection to the tower. The more interference or noise there is, the lower your signal quality will be.

It is possible to have bad signal quality, and good signal strength or bad strength and good quality. Ideally, the two need to be good for clear calls and data. If you have good signal strength, but terrible quality, you will still experience dropped calls, slow data speeds, and breaks in voice.

How to Measure Your Signal Strength in Decibels

Most phones have a “field test mode”. This can be found under your settings app on an Android, or by typing in a code on an iPhone. dBms are represented as rsrp signal strength.

dBm or decibel level is the most accurate way to test 5G, 4G, and LTE. It reflects exactly how much signal your phone is receiving. The field test mode doesn’t need a special app to be accessed, nor does it need your phone to be in a specific place. You can simply walk around your house or office to find the best signal strength.

Across all carriers, decibel readings, measured in decibel-milliwats (dBm) are the same, regardless of the way they choose to show them as “bars”. All carriers and all frequencies are measured in decibel milliwatts or dBm, including 4G, LTE, and 5G.

It is important to note that 5G signal is not available everywhere. Currently, 5G is only for data and all voice is over 4G. When you check your dBms you need to keep in mind that a great 5G signal may not mean great voice quality.

To find your signal strength on your phone, you need to look for the rsrp measurement. Rsrp signal strength is your phone’s way of displaying the current available dBms.

How Do I Find the RSRP Signal Strength on My Phone?

Methods vary from phone to phone, so read on to find step-by-step instructions for your device.

Field Test Mode For iOS Users

To find your iPhone 14, 15 and 16 field test mode, follow these steps:

  1. Turn off your phone's WiFi.
  2. Go to your phone’s “Phone” app and enter: *3001#12345#*. Hit the green button
  3. Choose LTE or Serving Cell Info
  4. Choose “RsrpRsrqSinr”
  5. Rsrp0 is your dBm
  6. Note: rsrp0 is your nearest tower, rsrp1 is your nearest back up tower.


  1. Dial *3001#12345#*
  2. Tap “LTE” on iOS 11-13 or “Menu” on iOS 14 - 16
  3. Tap “Serving Cell Meas”
  4. Your dBm is read as “rsrp0”

Note: This code may not work on all phones.

Field Test Mode for Android Users

The field test mode for Android devices varies by phone model and OS version, but it can usually be found under the Settings menu.

  1. Tap “Settings”
  2. Tap “About Phone”
  3. Tap “Status” or
  4. “Network”
  5. Tap “SIM Status”
  6. Your dBm or rsrp can be found under “Signal strength”

You can also use one of these apps to measure your phone's signal strength.

LTE Discovery: For Android

This is one of the best signal apps on the Play Store. It is packed full of features and is totally customizable. It will not only show you your dB level, but also your nearest cell tower.

Network Cell Info Lite: For Android

Network Cell Info provides the location of your signal on a map. It covers all cell networks, laying them out in easy-to-read color coding. Green = good, red = bad.

Open Signal: For Android and Apple

This great little app shows all nearby signals as an easy-to-understand graphic. Easily measure signal strength, data speeds and signal quality.

Network Signal Pro: For Android

This app gives you a summary of the whole network as well as any extra connections like WiFi laid out in a graphic or a graph. It shows tower locations, dBm strength and average, and other useful info.

What Does RSRP and RSSI Mean for Signal Strength?

RSRP stands for reference signal received power and is displayed in decibel milliwatts. It is the exact amount of signal being received by the device and is used to measure 4G, LTE and 5G. It takes an average of the power of the cell signals that your phone is getting from the tower and shows how strong those signals are. It will be shown on your phone as a dBm reading, between –110 and –50. The closer to –50 you are, the better your signal strength is.

Cellular routers for home or office internet, like the Peplink BR1 Mini and Br1 Pro 5G, also use a rsrp measurement for signal strength. This can be found in the router’s interface, either in it’s app or in your browser. Check your router’s manual to find out how to access the interface.

RSSI or Received Signal Strength Indicator shows how strong a radio signal is. Your phone has an RSSI which shows up as the bars counter. RSSI is a baseline of how strong the signal is after cable and antenna loss. The stronger the RSSI, the stronger your signal is. RSSI is always shown in the negatives, so the closer it is it 0 the better your received signal is.

What Do I Do with My Signal Strength dBm Reading?

Once you’ve tracked down your dBm reading, it’s time to start exploring your surroundings. Take your time walking around the property you’re looking to assess. dBm readings can take up to 30 seconds to refresh, so don’t rush.

The dBm should change based on your location, so keep track of which areas receive the best signal. This information can help you figure out the general direction of your nearest cell phone tower, pinpoint the rooms inside your building that get the best reception.

Here’s a general breakdown of common dBm signal ranges (and their possible bar assignations, depending on carrier/phone manufacturer):

Signal Strength General Results
-50 to -79 dBm Considered great signal (4 to 5 bars)
-80 to -89 dBm Considered great signal (4 to 5 bars)
-90 to -99 dBm Considered average signal (2 to 3 bars)
-100 to -109 dBm Considered poor signal (1 to 2 bars)
-110 to -120 dBm Considered very poor signal (0 to 1 bar)

Hopefully, you can find a spot or two that are close to -50 dBm!

What if My dBm is Lower than -95?

Please accept our condolences for your weak signal. Fortunately, we can direct to a wide selection of cell phone signal boosters to get your phone and smart devices back on track! The right signal booster can capture your weak signal, amplify it, then broadcast that newly boosted signal straight to your phone and devices for crystal clear coverage.

Contact Us

Signal Boosters is a leading provider of cell phone signal boosters for homes, vehicles, and commercial buildings. We specialize in consumer-friendly kits as well as customized RF systems for cellular, public safety two-way radio, DAS, and WiFi.

We’re here to assist with any issues you might be experiencing with poor cell service. Contact us today, or call us at 1-800-470-6777.

Interested in Learning More? Check Out Our Cellular Info Hub / WiFi Info Hub

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