Get FindTower App Today
Join over 500,000 users who have improved their cell signal with FindTower
Cell signal strength is measured in dBm (decibels relative to one milliwatt). Understanding these measurements helps you identify good vs poor coverage areas and optimize your device placement.
Learn what dBm readings mean and how they affect your call quality and data speeds.
Use signal readings to find the best locations for calls and data usage.
Identify signal issues and potential solutions for poor connectivity.
Signal strength of -50 to -79 dBm is excellent, -80 to -89 dBm is good, -90 to -99 dBm is fair, and -100 to -110 dBm is poor. Below -110 dBm you'll experience dropped calls and unusable data. You can check your exact reading in your phone's field test mode or settings.
On iPhone, dial *3001#12345#* and tap LTE > Serving Cell Meas to see rsrp (signal power). On Android, go to Settings > About Phone > Status > SIM Status or Signal Strength. The dBm reading is far more precise than bars, which each manufacturer defines differently.
Bars only measure signal strength, not network capacity. A tower can deliver strong signal while being overloaded with too many connected users. This is common at events, rush hour commutes, and dense neighborhoods. Signal quality metrics like SINR matter more for data speed than raw strength.
SINR (Signal-to-Interference-plus-Noise Ratio) measures how clean your signal is relative to interference. A SINR above 20 dB is excellent, 13-20 is good, 0-13 is fair, and below 0 means heavy interference. You can have strong dBm but poor SINR if nearby towers or electronics create interference.
Yes. 5G signals, especially mid-band and mmWave, attenuate faster than 4G LTE. You might see -75 dBm on LTE but -90 dBm on 5G from the same tower location. This is normal physics—higher frequencies lose power faster over distance and through obstacles.
Join over 500,000 users who have improved their cell signal with FindTower