How to compare carriers' coverage where you live

The best way to compare carrier coverage is to test each network yourself in the places that matter to you: home, work and your usual routes. Coverage maps are a useful first filter, but they are predictions, not measurements. A cheap prepaid SIM or eSIM on each network, plus a few readings in the right places, tells you far more.

Why coverage maps are only a starting point

Carriers publish maps that show where they expect coverage. They are built from computer models of masts, terrain and buildings. They are useful, but they have limits:

• They usually predict outdoor coverage. Indoors can be much weaker.
• They may not show the difference between a strong signal and a barely usable one.
• They can be optimistic at the edges of coverage.
• They may lag behind changes, like a new mast or one that was removed.

In some countries, the telecoms regulator publishes its own coverage checker that compares networks side by side. If yours does, use it alongside the carriers' maps.

Know which network a carrier really uses

Some carriers own their network. Others, often called MVNOs or virtual operators, rent space on someone else's network. A virtual operator usually has the same coverage as its host network, though features like 5G or Wi-Fi calling may differ. So when you compare carrier coverage, compare the underlying networks first. Testing two carriers that share one network will tell you little.

How to compare carrier coverage yourself

1. List the places that matter. Home, including the rooms you use most. Work. Your commute. Places you visit often.
2. Shortlist the networks. Use the maps to pick two or three networks that look promising.
3. Get a test SIM. A low-cost prepaid SIM or an eSIM trial lets you try a network without a contract. Many phones support a physical SIM and an eSIM together, so you can compare without swapping.
4. Measure in each place. Note signal strength in dBm, signal quality, network type (4G or 5G), and run a speed test.
5. Test at different times. Busy evenings and weekday rush hours show congestion that a quiet afternoon hides.
6. Make a call. Coverage for calls and coverage for data can feel different. Make a test call in each key spot.
7. Write it all down. Keep a simple record of place, time, network and readings.

What to measure

Signal strength (dBm). A rough guide for 4G is that around −80 dBm or better is strong, −90 to −100 dBm is fair, and below about −110 dBm is weak. Our guide on what a good signal strength in dBm is explains the ranges for 4G and 5G.

Signal quality. A strong signal with lots of interference can still perform badly. Quality readings show this.

Network type. Note whether you get 5G, 4G or something older at each place.

Speed and delay. Download, upload and ping show what the signal means in practice. Our guide on how to run a speed test that tells the truth explains how to test fairly.

Talk to people nearby

Neighbours and colleagues are a free source of real-world data. Ask which network they use and how it is indoors. A local community group can be useful too. Remember that their phone and the room they sit in matter, so treat it as a hint, not proof.

How to decide

Once you have readings, compare them place by place, not as a total. A network that is excellent in town but weak in your kitchen may still be the wrong choice. Ask yourself:

• Which network is usable in every place I listed?
• Where is each one weakest, and can I live with that?
• Do I have Wi-Fi in the weak spots, so Wi-Fi calling can cover the gap?
• Is the difference big, or within normal variation?

A map of your own readings makes the comparison much easier to see. Our guide to making your own signal map shows how.

Keep your records

Your readings are useful later too. If coverage gets worse after you sign up, a record from before gives you something concrete to show the carrier. See why keeping a signal history helps when you complain.

How CellRadar helps

CellRadar shows your live mobile signal in dBm with network type, carrier, band and cell ID. The signal map puts your own readings on a map, with offline maps and place search, and the speed test adds download, upload, ping and jitter. Signal history can be saved as PDF and CSV reports, which makes it easy to compare networks side by side.

Frequently asked questions

Are carrier coverage maps accurate?

They are useful predictions, mostly for outdoor coverage. Real indoor signal can be weaker, so test in the places you care about.

Do virtual operators have worse coverage?

They usually use the same masts as their host network, so coverage is often the same. Features like 5G access or Wi-Fi calling may differ.

Can I test two networks on one phone?

Many phones support a physical SIM and an eSIM at the same time, which lets you compare two networks without swapping cards.

How long should I test a network?

A few days covering weekdays, evenings and a weekend gives a fair picture of both coverage and congestion.