How to Check Mobile Signal Strength in Your Area

Updated March 2026 · All links and tools verified

Whether you’re choosing a new mobile network, troubleshooting poor signal, or checking coverage before moving house, knowing how to check mobile signal strength is essential. This guide walks you through every method — from quick online checkers to reading the actual signal data on your phone.

Method 1: Ofcom Coverage Checker (Quickest)

Ofcom’s official coverage checker is the best starting point because it compares all four major networks simultaneously.

How to use it:

1. Go to checker.ofcom.org.uk
2. Enter your postcode or address
3. Select “Mobile” as the service type
4. View coverage from EE, O2, Three, and Vodafone side by side

The Ofcom checker shows predicted outdoor coverage for voice, data, and whether you’re likely to get indoor signal. It’s based on network data and terrain modelling, so it’s a good general guide but not 100% accurate for every building.

Method 2: Network-Specific Coverage Checkers

Each network provides its own coverage checker with more detailed information than Ofcom’s tool. Here’s how to use each one:

EE Coverage Checker

1. Visit coverage.three.co.uk — wait, that’s Three. For EE, go to coverage.three.co.uk… Actually, visit coverage.ee.co.uk
2. Enter your postcode
3. Toggle between 4G, 5G, and indoor/outdoor views
4. EE’s checker also shows estimated speeds in your area

O2 Coverage Checker

1. Visit the O2 coverage map and checker
2. Enter your postcode or browse the map
3. O2 shows separate layers for 2G, 3G, 4G, and 5G
4. Look for “Strong” (green) vs “Limited” (amber) coverage indicators

Three Coverage Checker

1. Visit three.co.uk/coverage
2. Enter your postcode
3. Three’s checker shows indoor and outdoor coverage separately
4. Pay attention to the indoor coverage indicator — Three’s higher frequencies can struggle indoors

Vodafone Coverage Checker

1. Visit vodafone.co.uk/network/status-checker
2. Enter your postcode
3. Vodafone shows coverage type (indoor, outdoor, limited) for each technology
4. Their checker also shows planned network improvements in your area

Method 3: Check Signal Strength on Your Phone (Most Accurate)

For the most accurate signal reading, check the actual signal strength (measured in dBm) directly on your phone. This tells you exactly what signal your phone is receiving right now, in your exact location.

How to Check dBm on iPhone

1. Go to Settings → Cellular → Cellular Data Options
2. Look for Signal Strength or use the Field Test mode
3. To access Field Test: open the Phone app and dial *3001#12345#*
4. Navigate to LTE → Serving Cell Meas to find rsrp (signal power)

How to Check dBm on Android/Samsung

1. Go to Settings → About Phone → Status → SIM Card Status
2. Look for Signal Strength — it will show a dBm value
3. On Samsung: Settings → About Phone → Status Information → SIM Card Status
4. Some Android phones also show it under Settings → Network & Internet → SIMs → Signal Strength

How to Read Signal Strength (dBm)

Signal strength is measured in dBm (decibel-milliwatts). The scale is negative — closer to 0 is stronger:

Indoor vs Outdoor Coverage: Why They’re Different

One of the most common frustrations is having good signal outside but poor signal indoors. This happens because building materials block radio waves:

• Glass and wood — minimal signal loss (1-3 dB)
• Brick — moderate signal loss (6-10 dB)
• Concrete — significant signal loss (10-15 dB)
• Metal cladding — severe signal loss (15-25 dB)
• Energy-efficient windows — surprisingly high loss (5-10 dB) due to metallic coatings

Modern energy-efficient buildings are often the worst for mobile signal. The same insulation that keeps heat in also blocks radio waves. If you’re in a new-build office or home, indoor signal may be significantly worse than the coverage checker suggests.

Which Frequencies Penetrate Buildings Best?

Lower frequencies penetrate buildings better. This is why EE’s 700MHz 4G coverage often works indoors when higher-frequency signals don’t. 5G, which uses higher frequencies, typically has worse indoor coverage than 4G.

What to Do If You Have Poor Signal

If you’ve checked your signal and it’s poor, here are your options, from simplest to most involved:

1. Enable WiFi Calling (Free, Instant)

WiFi calling uses your broadband connection to make and receive calls and texts when mobile signal is poor. It’s free, built into most modern phones, and works on all four major networks. See our complete guide to WiFi calling for setup instructions.

2. Move to a Window or Higher Floor

Signal strength can vary dramatically within a building. Moving to a window-facing position or a higher floor can improve signal by 10-20 dBm — the difference between no signal and usable signal.

3. Switch Networks

Different networks use different mast locations and frequencies. If one network is poor in your area, another might be excellent. Use the coverage checkers above to compare, or check our mobile network comparison for a full breakdown.

4. Use a Signal Booster (Femtocell)

Some networks offer femtocells — small devices that create a mini mobile mast in your home or office using your broadband connection. These are different from illegal signal amplifiers:

• Vodafone Sure Signal — available for home and business use
• Three Home Signal — free for Three customers
• EE Signal Box — available on request for areas with poor coverage

5. Use an External Antenna (For Vehicles and Rural Properties)

If you’re in a very rural area or need signal in a vehicle, an external antenna can significantly improve reception. These are legal and work by capturing a weak outdoor signal and routing it to your device via a cable. They’re commonly used with mobile broadband routers.

Signal Checking Apps

Several apps can help you monitor and map signal strength:

• OpenSignal — crowdsourced coverage maps based on real user data. More accurate than network predictions in many areas.
• Network Cell Info (Android) — detailed technical information about your connection including dBm, cell tower ID, and frequency band.
• Speedtest by Ookla — while primarily a speed test, it also logs your connection type and can help identify signal issues.
• Coverage Critic — independent coverage analysis with user reports and comparisons.

For Businesses: Getting the Best Coverage

If you’re a business dealing with poor mobile signal, the stakes are higher — missed calls mean missed revenue. Here’s what we recommend:

1. Audit your current coverage — check signal at every desk, meeting room, and common area
2. Consider a multi-network approach — use the best network for each location
3. Enable WiFi calling on all devices — it’s free and provides an immediate backup. See our guides for Android and iPhone
4. Talk to us — we can do a free signal assessment at your premises and recommend the best solution

Frequently Asked Questions

How do I check which mobile network has the best coverage in my area?

Use Ofcom’s coverage checker at checker.ofcom.org.uk to compare all four networks at your postcode simultaneously. For more detail, check each network’s individual coverage tool.

Why does my phone show full bars but data is slow?

Signal bars show connection strength, not speed. You might have a strong connection to a congested mast, resulting in good bars but slow data. This is common in busy areas during peak hours. Try speed testing at different times of day.

Is there an app that shows the best network in my area?

OpenSignal is the best app for this. It uses crowdsourced data from real users to show which network performs best at any location, including speed and reliability metrics.

Why is my signal worse indoors?

Building materials block radio waves. Concrete, metal, and even energy-efficient windows can reduce signal by 10-25 dBm. WiFi calling is the easiest solution — see our WiFi calling guide.

Can I improve mobile signal without changing network?

Yes. Enable WiFi calling (free), move closer to windows, ask your network about a femtocell device, or use an external antenna for rural properties. See the “What to Do If You Have Poor Signal” section above for full details.