Apps that show signal do one of three things: they measure the signal where you are, they map where others measured it, or they lead you to it. Which you need depends on whether you are testing your network or looking for one.
Opensignal
Good for: testing your connection and comparing operators
Speed, responsiveness and video tests on Wi-Fi and 2G to 5G, your history of tests on a map, how much of the time you have no signal, and coverage maps of the major operators worldwide. LastBar vs Opensignal.
CellMapper
Good for: tower locations and frequency bands
A crowdsourced map of towers, their sectors and bands, worked out from what its users upload, with coverage per carrier and band. The Android app reads more of the radio than an iPhone allows. LastBar vs CellMapper.
Android, and an iPhone app
LastBar We built this
Good for: getting to signal when you have none
A map of where phones measured signal, and where they measured none, made by the people who use it, carrier by carrier. It keeps the map of the places around you and of the areas you save on your phone, so Find Signal can give you the distance and direction to the nearest signal with no connection: for an emergency call on any carrier, a call or SMS on your own, or data. It shows the emergency numbers of the country you are in, and water, shelter, clinics, police and fuel from OpenStreetMap. Android phones map signal in the background as you go; an iPhone maps while the app is open. Where nobody has been with it yet, the map is empty.
Android 8.0 and up, iPhone with iOS 16 and up · Free, with Pro bought once
nPerf
Good for: speed tests, with coverage maps of 2G to 5G
A speed test of download, upload and latency for almost any connection, and a map of mobile coverage in your area. LastBar vs nPerf.
Android, iPhone and iPad, PC and Mac
Network Cell Info Lite
Good for: a live signal meter on Android
Shows the signal of your carrier and Wi-Fi about once a second, logs it along your route on a map, supports two SIMs, and adds a speed test.
Android · Free, with an ad-free paid version
Which one?
- Is my network slow? Opensignal or nPerf.
- Which tower am I on, which band? CellMapper or Network Cell Info.
- I have no bars: where is the nearest signal? LastBar, which works offline.
What each app does is as its own website or store listing said on 26 October 2026. Apps change; check before you rely on one.
