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What is Signal Strength and How Much Do You Need?
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There’s nothing worse than having no signal, but what exactly does it mean for your connection? Here’s everything you need to know about signal strength, including what it is, what a good signal strength is, and how to improve your signal.
By Virgin Media Edit
- Published
- 18 March 2025
What is signal strength?
Signal strength is how strong or weak a signal is when it reaches a device, like a phone, radio, or Wi-Fi router. It’s usually measured in decibels (dBm), with a higher number meaning a stronger signal, and a lower number meaning a weaker one.
Signals are used to send information, such as phone calls, text messages, internet data, and TV broadcasts, through the air or over wires. When your signal strength is strong, your connection will be clear and fast, meaning you can hear phone calls without interruption, load websites quickly, and stream videos without buffering.
But when the signal is weak, your connection gets worse, and you’re more likely hear static during a call, experience slow internet speeds, or see a video pause frequently to load.
For example, if you’re close to a Wi-Fi router with no walls in the way, your signal strength will likely be very strong. But if you move to a different room or go outside, the signal might weaken because of the distance and obstacles in between.
What can affect your signal strength?
There’s lots of things that can impact your signal strength and make it stronger or weaker, from how far you are to the source of your connection to physical barriers and your device itself.
Some of the most common factors to consider include:
The farther you are from the source of the signal, like a cell tower or Wi-Fi router, the weaker the signal becomes. Signals lose strength as they travel, so if you're close to a router or tower, you'll likely have a strong connection. But as you move away, the signal has to work harder to reach you, causing it to weaken. This is why your phone signal might be strong in one room but weak or nonexistent in another.
Walls, doors, floors, and other objects can block or weaken signals. Thick walls made of concrete, brick, or metal are especially hard for signals to pass through, and even glass and wood can reduce signal strength. If your Wi-Fi router is in the living room, you might get a weaker signal in the bedroom if there are several walls in between. This can impact your RSSI level, which is the signal strength between your device and your router.
Other electronic devices, such as microwaves, cordless phones, and Bluetooth devices, can interfere with signals. These devices operate on similar frequencies, which can cause them to compete for space in the airwaves. This can lead to slower internet speeds or dropped connections, especially when multiple devices are used at the same time.
Bad weather like heavy rain, snow, or strong winds can weaken wireless signals, especially for satellite and cell phone signals. Trees, hills, and even buildings can also block or scatter signals. For example, you might notice that your phone signal drops during a storm or when you’re surrounded by tall buildings.
When too many people are using the same network at once, the signal can become weaker or slower. This often happens in crowded places like stadiums, concerts, or busy city centers. The network gets overloaded, which reduces the quality of the connection for everyone.
When too many people are using the same network at once, the signal can become weaker or slower. This often happens in crowded places like stadiums, concerts, or busy city centers. The network gets overloaded, which reduces the quality of the connection for everyone.
What is a good signal strength?
Signal strength is measured in decibels (dBm) for cell signals and Wi-Fi signals, and the closer the number is to zero (even though it’s negative), the stronger the signal. Generally speaking, a signal strength of -50 dBm is very strong, while -100 dBm is weak.
But what is considered a good signal change depending on whether you’re talking about WiFi or cellular signal:
Good signal strength for WiFi
For WiFi signals, a good signal strength is usually between -50 dBm and -60 dBm. If your Wi-Fi signal is stronger than -50 dBm, you should have a very fast and stable connection. Between -60 dBm and -70 dBm is still decent for browsing and streaming, but the connection may not be as fast. Once the signal drops below -70 dBm, you might notice slower speeds, buffering, or connection drops.
Not all internet speed issues are caused by a bad signal strength. If you’re signal strength is good but you’re still experiencing speed issues, your broadband package may be what’s causing you issues. Not sure if your broadband is fast enough? Use our helpful broadband speed checker to see if your connection is up to speed.
Good signal strength for Mobile
For mobile signals, a good signal strength for 4G or 5G networks is usually between -70 dBm and -90 dBm. Anything closer to -70 dBm means a strong and reliable connection, while between -90 dBm and -100 dBm may still work but could cause slower data speeds or poor call quality.
Once you get below -100 dBm, the signal is too weak for most activities, and you might struggle to make calls or load websites.
How can you test your signal strength?
To test your signal strength, you can simply look at the signal bars on your phone or device. However, the bars are just a rough guide, and measuring the dBm value gives you a more accurate idea of how strong your signal really is.
You can measure your dBm value to check the strength of your WiFi or cell signal using your phone or computer. Most devices don’t show the dBm value directly, but you can find it in the settings or by using special apps.
If you want to measure your Wi-Fi signal strength, you can check it on your phone or computer:
On an iPhone, you’ll need to download a Wi-Fi analyzer app from the App Store because Apple doesn’t show dBm values directly in the settings.
On an Android phone, you can go to Settings > Wi-Fi and tap on the network you’re connected to. It should show the signal strength in dBm.
On a Windows computer, open the Command Prompt and type 'netsh wlan show interfaces', then press Enter. Look for the signal value, which is shown as a negative number (like -60 dBm).
On a Mac, hold down the Option key and click the Wi-Fi icon in the menu bar. A drop-down menu will show the signal strength (RSSI) in dBm.
You can also measure your mobile signal strength in dBm:
On an iPhone, open the Phone app and dial 3001#12345#, then press Call. This opens a hidden "Field Test" menu. Look for the dBm value under "Serving Cell Meas."
On an Android phone, go to Settings > About Phone > Status > SIM Status (or similar) and look for "Signal strength." The value will be shown in dBm.
How can I improve my signal strength?
Improving your signal strength can make your internet faster and your phone calls clearer. Here are some simple and effective ways to boost your Wi-Fi or cell signal:
1. Move Closer to the Source
One of the easiest ways to improve your signal is to move closer to the Wi-Fi router or cell tower. Signals weaken as you move farther away from the source. If your Wi-Fi is weak in certain rooms, try using the internet closer to the router. For cell signals, stepping outside or moving to a window can help you connect to a stronger signal.
2. Remove Obstacles
Walls, furniture, and other physical barriers can block or weaken signals. Try to position your Wi-Fi router in a central, open location to reduce interference. For cell signals, avoid standing behind walls or in basements where signals have trouble reaching.
3. Reduce Interference from Other Devices
Other electronic devices like microwaves, cordless phones, and baby monitors can interfere with your WiFi signal. If you’re using a 2.4 GHz Wi-Fi network, switch to a 5 GHz network (if your router supports it) to help reduce interference and improve speed.
4. Use a WiFi Extender or Mesh System
If your WiFi signal is weak in certain parts of your house, you can use a WiFi extender or mesh WiFi system to help boost your connection throughout your home. A WiFi extender boosts the signal from your router and helps it reach farther, while a mesh system uses multiple devices placed around your home to create a stronger and more even WiFi signal.
5. Update Your Router or Phone
Old routers and phones may not support the latest and fastest signal types. If your router is more than five years old, upgrading to a newer model can give you a stronger and more stable signal. The same goes for phones — newer models are better at picking up weak signals.
6. Change the Router’s Position
The location of your router can make a big difference to your signal strength. Place it in a central spot, off the floor, and away from walls and metal objects. Keep it elevated on a shelf or table, and make sure it’s not surrounded by clutter. This helps the signal spread more evenly throughout your home.
Does your WiFi signal affect internet speed?
Yes, your WiFi signal is often closely linked to internet speed. A strong WiFi signal allows data to travel quickly and without interruptions, giving you fast internet speeds for things like streaming, gaming, and video calls, while a weak can slow down your internet connection, causing buffering, lag, and longer loading times.
When the Wi-Fi signal is strong, your device can communicate easily with the router, which means data can flow smoothly. For example, if your Wi-Fi signal strength is around -50 dBm (which is very strong), you should be able to stream high-quality videos, make clear video calls, and download files quickly. But if the signal drops to around -80 dBm or lower, the connection may become unstable, causing videos to buffer, calls to drop, and websites to load slowly.
Remember, not all internet speed issues are caused by a bad signal strength. If you’re signal strength is good but you’re still experiencing speed issues, your broadband package may be what’s causing your speed issues.
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