Cell Signal Strength
Bars lie. Learn what your signal really is in dBm, run a true speed test, and find the nearest tower so you can fix weak coverage instead of guessing.
What your dBm number means
Cell signal strength is measured in dBm, a negative number where closer to zero is stronger. A reading of -75 dBm is far better than -105 dBm. Use this scale to judge your real signal:
| Signal (dBm) | Rating | What it feels like |
|---|---|---|
| -50 to -79 dBm | Excellent | Full speed, reliable calls and data |
| -80 to -89 dBm | Good | Solid performance for most uses |
| -90 to -99 dBm | Fair | Usable but slower, occasional hiccups |
| -100 to -109 dBm | Weak | Buffering, slow loads, shaky calls |
| -110 dBm or lower | Poor | Dropped calls, data often fails |
How to improve a weak signal
- →Find your nearest tower on the map and note its direction.
- →Move toward windows or higher floors that face that tower.
- →Aim a signal booster antenna at the serving tower, not randomly.
- →Compare carriers: the one with the closest tower usually wins.
Knowing the exact tower serving you turns signal fixes from guesswork into a targeted job. See which carrier has the nearest tower to your address:
Cell signal strength FAQ
What is a good cell signal strength in dBm?+
Signal is measured in dBm and closer to zero is better. Around -50 to -79 dBm is excellent, -80 to -89 dBm is good, -90 to -99 dBm is fair, -100 to -109 dBm is weak, and -110 dBm or lower usually means dropped calls and stalled data.
Why are signal bars unreliable?+
Bars are not standardized. One phone may show four bars at -100 dBm while another shows two. The actual dBm reading and your real download speed tell you far more than the bar icon.
How can I improve a weak cell signal at home?+
Find your nearest tower on the map and face windows or antennas toward it, move to a higher floor, reduce obstructions, or install a signal booster aimed at that tower. Switching to a carrier with a closer tower is the most reliable fix.
Does distance to the tower affect signal strength?+
Yes. The farther you are from the serving tower, and the more walls, hills, and trees in between, the weaker the signal. Low-band frequencies penetrate obstacles better than mid-band or mmWave.
How do I test my real connection speed?+
Use the built-in speed test to measure live download speed, upload speed, and ping. Pairing speed with signal strength shows whether weak data is a coverage problem or network congestion.
Check your signal and find your tower
Free on iPhone, no account needed.