Weak signal has three common causes: the network does not reach your address, your building blocks it, or your phone or settings are the problem. Finding which one you have tells you what will work. This guide takes you through checks and fixes, in the order that saves time and money.
Work out where the problem is
| What you notice | Likely cause | What to try |
|---|---|---|
| Weak signal everywhere you go | Phone, SIM or provider fault | Restart, test the SIM in another phone, then contact your provider |
| Weak signal in one place, good elsewhere | Local coverage | Check your postcode and try another network |
| Fine outdoors, poor indoors | Your building | Try an upper floor or a window, then Wi-Fi calling |
| Calls drop but data works | Calling set up | Switch on 4G calling and Wi-Fi calling |
Ofcom’s own advice is to find out whether the problem is in one place or everywhere. If you have not used your phone somewhere before, check the coverage that should be there first.
Check your postcode
Ofcom’s Map Your Mobile tool shows two things for your postcode. The first is coverage, which is a prediction supplied by the networks. The second is performance, which comes from crowdsourced measurements and shows how often people in your postal district can stream video or make a video call when they have a signal.
It gives separate readings for indoors and outdoors. Outdoors, it separates “variable” signal, usually enough for calls, texts and lower quality video, from “good” signal that supports streaming. It covers EE, O2, Vodafone and Three, and lists the smaller brands that use each one.
Ofcom is open about the limits. Predictions can differ from what you get, because your signal depends on how strong the nearest mast is, how far away it is, and the quality of your phone’s antenna. Enter your home, work and the places you spend time, and treat the map as a guide, not a promise. For the national picture, see which network tests best nationally.
Turn on Wi-Fi calling and 4G calling
Wi-Fi calling sends your calls and texts over your broadband when the mobile signal is weak. It does not use your mobile data, and calls still use your normal minutes. All four networks support it, and most smaller brands do, though handset support varies.
- iPhone: Settings, then Phone, then Wi-Fi Calling.
- Samsung: Settings, then Connections, then Wi-Fi Calling.
- On other Android phones, look under network or calling settings.
Check your emergency address when asked, and update it if you move. Wi-Fi calling will not rescue a poor broadband line, and it can fail on networks that ask you to log in on a page, such as hotels.
Because 3G is now switched off, calls on a weak signal rely on 4G calling. Make sure it is on, and that your phone supports it. If you are unsure, see 5G signal indoors, which also covers how newer bands behave inside buildings.
Other fixes inside your home
- Move to an upper floor or a window. Dense walls, basements and rooms in the middle of a building are the hardest for signal. Energy efficient glass can also weaken it.
- Higher frequency bands used for faster 5G travel less well through walls than lower bands.
- Use apps such as WhatsApp or FaceTime over Wi-Fi. They do not use your mobile number, so they will not replace calls to it.
- Try a second network. Ofcom suggests a two SIM approach if you need coverage in places where different networks work best. See using an eSIM for a second network.
- Consider the phone. Ofcom says the handset can affect reception, and some network checkers let you choose the model.
Boosters and the rules
Only a signal booster that meets Ofcom’s rules is legal to use. Since June 2022, you can buy and install a licence exempt static indoor repeater without a licence, if it meets Ofcom’s requirement, known as IR 2102. Using other equipment is a criminal offence, and it can interfere with emergency services. The old network devices, such as EE’s Signal Box and Vodafone’s Sure Signal, are no longer available.
Compliant boosters need a usable outdoor signal to amplify, and they cost far more than the cheap imports sold online. Try Wi-Fi calling first.
If nothing works
Your contract is with your provider, so it is responsible for fixing faults and keeping you updated. Report the problem in writing, with dates and places. Ofcom says that if you have been without service for some time, you may have the right to leave without penalty, depending on your contract terms. Our guide to leaving a phone contract early explains how exit charges work, and leaving a network with poor signal covers keeping your number.
Ofcom does not investigate individual complaints, but reporting a problem helps it spot patterns.
Choosing a network for signal
Test before you commit. A rolling plan, such as a 30 day plan to test a network, lets you try one at your home. Many cheaper brands use the same masts as the big four, so small brands on the same masts can be a low cost way to try a network.
In the countryside, the Shared Rural Network reached its target of 4G from at least one network across 95% of the UK landmass in 2025, a year early. The next stage focuses on areas with no 4G at all, mostly in Scotland, with 44 new shared masts planned. Local gaps remain, so check your own postcode.
Where to go next
Once you know which network works for you, find a plan on the network that works at your address and filter by it.
FAQs
Does Wi-Fi calling work for emergency calls?
Yes, but your phone needs an emergency address on file so the call can be routed. Check it when you set up Wi-Fi calling and again if you move house.
Is a new phone likely to improve my signal?
It can help. The antenna design differs between models, and some provider checkers let you pick the handset you plan to use. A faulty or damaged phone is worth ruling out first by trying your SIM in another handset.
Why is my signal worse in a modern building?
Energy saving windows, thick insulation and concrete can all weaken signal. Try a window or upper floor, then Wi-Fi calling.