How to check your mobile signal strength (in dBm).
By SignalFix · Facts checked 2026-10-02
Why bars lie
Bars are drawn by your phone maker, and each maker draws them differently. Two phones in the same spot can show three bars and one bar. The number behind the bars, measured in dBm, is the same everywhere, which is why we measure in dBm and only use it as proof.
dBm readings are negative. Closer to zero is stronger: −70 is better than −110.
On Android
- Open Settings → About phone → Status (on some phones, SIM status). Look for Signal strength in dBm. The path varies by brand.
- On many phones, dialling
*#*#4636#*#*opens a "Phone information" menu with more detail. It's blocked on some models, including many Samsung phones. - Free apps such as Network Cell Info or NetMonster often show RSRP, RSRQ and SINR more reliably.
On iPhone
- Turn Wi-Fi off.
- Open the Phone app, dial
*3001#12345#*and press call. Field Test opens. - Look for RSRP (dBm) under the LTE or 5G section. The layout changes between iOS versions.
A phone only measures its own SIM's network. To compare Jio and Airtel, measure each SIM separately.
What the numbers mean
| Reading | Excellent | Good | Fair | Poor |
|---|---|---|---|---|
| Signal strength, RSRP (dBm) | ≥ −80 | −80 to −90 | −90 to −100 | < −100 |
| Signal quality, RSRQ (dB) | ≥ −10 | −10 to −15 | −15 to −20 | ≤ −20 |
| SINR (dB) | ≥ 20 | 13 to 20 | 0 to 13 | ≤ 0 |
These are typical vendor guidance for 4G (LTE), not an official standard. Strength tells you how much signal arrives; quality and SINR tell you whether calls will hold. In a busy office you can have strong signal and poor quality.
Log every room like a SignalCheck
- Keep doors and windows as you normally do.
- Stand where you actually use the phone: bed, desk, sofa.
- Wait 10–15 seconds for the reading to settle, then note it.
- Do every room, then the balcony or terrace for comparison.
- Repeat for each SIM.
If the balcony reads well and two bedrooms read poorly, the network reaches you and the walls are the problem. That's the pattern a SignalCheck maps properly, with a report you can act on.