Short answer
On Android, several apps can read your phone's measured signal (RSRP, RSRQ, SINR) and the cell's ID, including CellMapper, Network Cell Info, NetMonster, LTE Discovery, and Cell Surveys. On iPhone, none can, because iOS does not give apps those values; iPhone apps show the network type, speed tests, maps of other users' data, or an estimate. Choose by the job: a live reading, a tower map, a speed test, or a map of your own home or route.
By Eli TrevinoUpdated
The Short Version
The biggest difference between signal apps is not the app; it is the phone. Android lets apps read the measured signal and the ID of the cell you are on. iOS does not, for any app (here is why). So on an iPhone every signal app is really a speed test, a map of other people's data, or an estimate.
What Each App Measures
| App | Platforms and price | On Android | On iPhone |
|---|---|---|---|
| Cell Surveys | iPhone, Android. Free, no ads; optional Pro subscription | Measured RSRP, RSRQ, SINR, PCI, and cell ID; neighbor cells in surveys | Network type and an estimated level |
| CellMapper | Android, and iPhone since March 2026. Free with ads | RSRP, RSRQ, SINR, and cell ID; band on most phones | The map and your network type |
| Network Cell Info | Android only. Lite is free with ads; the full app is a one-time purchase | RSRP, RSRQ, and RSSNR; serving and neighbor cells, with PCI and band on phones that report them | No iPhone app |
| NetMonster | Android only. Free with ads | RSRP, RSRQ, SINR, and CQI; cell IDs, PCI, band, and neighbor cells | No iPhone app |
| LTE Discovery | Android only. Free with ads | RSRP, RSRQ, and SINR; PCI, band, and channel numbers | No iPhone app |
| Opensignal | iPhone, Android. Free, no ads | Signal strength; detailed values not documented | Speed and video tests, coverage map |
| nPerf | iPhone, Android. Free with ads | Not documented | Speed, browsing, and streaming tests; coverage map |
| Speedtest by Ookla | iPhone, Android. Free with ads | Not documented | Speed and video tests; coverage maps |
| FCC Mobile Speed Test | iPhone, Android. Free, no ads | Records RSRP, RSRQ, SINR, PCI, and cell ID with each test; shows speed results | Speed tests only |
Maps, Speed Tests, and Exports
| App | Map | Speed test | Export |
|---|---|---|---|
| Cell Surveys | Your own signal heatmap, plus Everyone's coverage (all users' average signal over 30 days) | No | CSV; ZIP on Android |
| CellMapper | Crowd-sourced coverage and tower map; tower positions are calculated from users' readings | No | CSV |
| Network Cell Info | Your own route colored by signal, plus a crowd-sourced best-signal finder; no tower database | Yes | KML and CSV formats |
| Opensignal | Crowd-sourced coverage map; a compass points toward the strongest signal | Yes | Not documented |
| nPerf | Crowd-sourced coverage map | Yes | No user export documented |
| Speedtest by Ookla | Crowd-sourced coverage maps showing the best technology in each area | Yes | Not documented |
| FCC Mobile Speed Test | None in the app; tests feed the FCC's National Broadband Map | Yes | ZIP of CSV or JSON |
Which App for Which Job
- Checking a house, an office, or a room: you want your own readings on a map, room by room. Apps that log your signal with GPS do this; see how to check coverage at a house.
- Finding where the towers are: CellMapper's map places towers from its users' readings. Treat the positions as estimates; CellMapper says itself that they are calculated.
- Testing speed: Speedtest, Opensignal, nPerf, and the FCC app all run speed tests on both platforms.
- Disputing your carrier's coverage claims: the FCC Mobile Speed Test app is the one whose tests count toward a challenge to the FCC's National Broadband Map.
- Logging a drive: you want an app that records in the background; see tracking coverage on a road trip.
- Checking a new small cell: you need the PCI, which means Android; see small cell baselines with the app.
Where Cell Surveys fits. The free Cell Surveys app is built for mapping your own signal: it records in the background as you go and turns every reading into a colored square on a heatmap, with surveys you can replay and export. It does not run speed tests or map towers.
