Short answer
Apple does not let third-party apps read the iPhone's measured signal strength (RSRP), signal quality (RSRQ and SINR), or the ID of the cell it is connected to, and Apple's developer support confirmed in 2026 that no public API provides them. An iPhone app that shows your signal in dBm is estimating it. To see the measured numbers, open Apple's hidden Field Test Mode, or use an Android phone, where apps can read them directly.
By Eli TrevinoUpdated
What iOS Lets Apps See
An app can only show what the operating system hands it. On Android, apps can read the same radio measurements the phone uses itself. On iPhone, Apple keeps nearly all of them private.
| Measurement | iPhone apps | Android apps |
|---|---|---|
| Network type (5G, LTE) | Yes | Yes |
| Carrier name and network code | No longer on current iOS. Apple deprecated the interface in iOS 16, and it now returns placeholder values. | Yes |
| Signal strength (RSRP) | No | Yes, on most phones |
| Signal quality (RSRQ, SINR) | No | Yes, on most phones |
| Cell ID and PCI | No | Yes |
| Neighbor cells | No | Yes, depending on the phone |
This is not an app developer's choice. Asked on Apple's developer forums in August 2026 for RSRP, RSRQ, SINR, PCI, and cell ID, an Apple engineer answered: "No public API provides the level of information you're describing." The FCC's own Mobile Speed Test app runs into the same wall: it records these values with each test on Android, and not on iPhone.
So What Do iPhone Signal Apps Show?
Look closely at any iPhone app that talks about signal and it is doing one of three things: showing the network type, running a speed test, or showing a map built from other people's data. Some also show an estimated signal level, worked out from indirect clues. An estimate can tell a strong spot from a dead one, but it is not a measurement, and it cannot be compared with the dBm reading from an Android phone or from Field Test Mode.
The Cell Surveys iPhone app is one of these. It estimates the level from the network type and from how quickly and reliably the cellular connection responds, which is good enough to map dead spots and weak rooms. Treat its numbers as estimates, not readings.
How to See the Real Numbers on an iPhone
iPhones have a built-in diagnostic screen called Field Test Mode. Open the Phone app, dial *3001#12345#, and press call. Apple does not document it and changes what it shows between iOS versions, so look for entries labeled RSRP, RSRQ, and SINR or SNR rather than a fixed menu path.
- It is a spot check. The values are not timestamped and do not always refresh, so wait, move, and check that the numbers change before trusting one.
- It does not record anything. Field Test Mode shows the current value only, with no history and no map.
- Reading the numbers: for LTE and 5G, an RSRP better than −90 dBm is good and below −110 dBm is effectively no service. Here is the full scale, with RSRQ and SINR.
When You Need Measured Data
If you need the actual numbers over time or across a whole house, use an Android phone on the carrier you care about. Android apps can log measured RSRP, RSRQ, and SINR with GPS at every step. Here is what each signal app can measure on iPhone and on Android.
Map it either way. The free Cell Surveys app runs on both. On Android it records measured RSRP, RSRQ, and SINR with the cell's PCI and ID. On iPhone it maps an estimated level, which still shows where the dead spots are.
