How to check your real signal strength on Android

The quickest way to check signal strength on Android is to find the dBm number, not to count the bars. Almost every phone shows it on a status screen inside Settings, and a signal app can show it live as you move around. The closer the number is to zero, the stronger the signal.

Why the bars are not enough

Bars are a rough summary. Each phone maker decides how many bars a given signal earns, so two phones side by side on the same network can show different bars. Bars also update slowly and squash a wide range of readings into four or five steps.

The dBm number is the measurement the bars are built from. dBm stands for decibel-milliwatts, a unit for very small amounts of radio power. Because your phone receives only a tiny fraction of a milliwatt, the numbers are negative. So −85 dBm is a stronger signal than −105 dBm.

If you want to understand the scale itself, read what dBm means.

How to check signal strength in Android settings

Android hides the number, but it is there on nearly every phone. Menus differ between brands, so the search bar is your friend.

1. Open Settings.
2. Tap the search bar and type "SIM status" or "Status". On many phones it sits under About phone.
3. Open the SIM status screen for the SIM you want to check.
4. Find the line called Signal strength. It shows a value in dBm, often with an "asu" number next to it.
5. Wait a few seconds and read it again. The value refreshes, so one glance is not enough.

If your phone has two SIMs, each one has its own entry. Check the SIM you use for mobile data.

Some phones also have a hidden testing menu that you open by dialling a code in the phone app. It is not available on every model and it contains settings you should not change, so the status screen is the safer place to look.

What to look for when you read the number

On 4G, the number shown is usually RSRP, short for reference signal received power. It measures the strength of a known signal sent by the cell, which makes it a fair comparison from place to place. As a rough guide, anything better than −80 dBm is excellent and −90 dBm or better is good. Between −90 and −100 dBm is fair, below −100 dBm data gets slow, and below −110 dBm you are close to losing service.

On 5G the ranges are similar. There is a fuller breakdown, including quality numbers, in what counts as a good signal strength in dBm.

Always note the network type next to the reading. A strong 4G signal and a weak 5G signal can exist in the same spot, and your phone may switch between them.

How to get a reading you can trust

A single reading tells you very little, so plan to check signal strength more than once. Signal moves up and down as you turn, as people walk past and as the cell gets busier. To get a fair picture:

1. Hold the phone the way you normally do, not pressed against the window.
2. Stay in one place for about 30 seconds and note the range, not just one value.
3. Check at different times of day, since evenings are often busier.
4. Repeat in a few rooms, near windows and in the middle of the house.
5. Write down the network type each time, because 4G and 5G readings are not directly comparable.

Your hand and your case matter a little too. Thick metal cases, or gripping the edges where antennas often sit, can lower the reading by a few dB.

Signal strength is not the same as speed

A good number does not promise fast internet. Strength tells you how loud the cell is at your phone. Speed also depends on interference, how many people share the cell and the connection behind the mast. That is why you can see full bars but slow internet. If the dBm looks healthy but pages still crawl, a speed test is the next step.

Other lines worth reading on the status screen

While you are there, look at the rest of the screen:

• Network type: LTE means 4G, NR means 5G, and names like HSPA mean an older network.
• Mobile network: confirms which carrier you are on, which matters when you travel or roam.
• Service state: "In service" means you are connected. "Emergency calls only" means your normal service has dropped.

A few phones also show the band or cell ID here, but most do not.

How CellRadar helps

CellRadar shows your live mobile signal in dBm, together with the network type, carrier, band and cell ID, and explains the number in plain words. A home-screen widget and an optional live readout in the notification bar let you check signal strength as you walk from room to room. It cannot make the signal stronger, but it shows you where it is better and keeps a history you can save as a PDF or CSV report.

Frequently asked questions

Is −100 dBm a good signal?

It is on the weak side. At around −100 dBm on 4G, calls usually work, but data can be slow and patchy, especially indoors.

Why does my reading change when I am standing still?

Radio signals bounce off walls, people and passing cars, and the load on the cell changes all the time. Swings of a few dB are normal, so watch the range over a minute.

Can I check my signal without installing an app?

Yes. On most Android phones, search Settings for "SIM status" to see the dBm reading. An app adds live updates, history and extra details such as the band.

What does asu mean next to the dBm number?

ASU stands for arbitrary strength unit. It is just a different scale for the same reading, so stick with the dBm value.