How to Determine Wi-Fi Signal Strength: From Theory to Practice

A weak Wi-Fi signal is one of the most common causes of slow internet and connection drops during streaming or video calls. But how can you tell if the problem is actually signal strength, and not your provider's plan or router settings? In this article, we'll look at how measure Wi-Fi signal strength on different devices, what do the mysterious ones mean? dBm, and what values ​​are considered normal for stable operation.

Many users mistakenly believe that the number of "bars" on the Wi-Fi icon on their phone or laptop reflects the actual signal strength. In fact, these indicators only show relative level — they are not precise and can be misleading. For example, three divisions out of four on iPhone can correspond to either an excellent signal (-50 dBm) or a mediocre one (-75 dBm), at which point 4K video will begin to “slow down”.

We have prepared step-by-step instructions for all popular devices: from smartphones to Android And iOS to computers with Windows or macOSYou'll also learn how to check the signal directly on the router and what to do if the readings are less than ideal. Let's start with the theory—without it, it's difficult to understand which numbers on the screen mean "good" and which mean "bad."

What is dBm and how to read Wi-Fi signal strength?

Wi-Fi signal strength is measured in decibels-milliwatts (dBm) — a logarithmic unit that shows the signal power relative to 1 milliwatt. less value in dBm, tem stronger signal. This is counterintuitive (large numbers are usually associated with "good"), so many users are confused.

Here's a simple scale to rate signal quality:

Important: a difference of only 3 dBm means doubling or halving the signal power. For example, -65 dBm is twice as weak as -62 dBm. Therefore, even small changes in the position of the router or device can significantly affect connection stability.

In addition to signal strength, Wi-Fi quality is affected by:

• 📶 Network frequency: 2.4 GHz passes through walls better, but is more congested; 5 GHz is faster, but spreads worse.
• 🔄 Channel congestion: If your neighbors use the same channel, your speed will drop even with a strong signal.
• 📡 Router antenna type: Omnidirectional ones cover a larger area, but penetrate walls less effectively than directional ones.
• 🛡️ Interference: Microwaves, cordless phones, and Bluetooth devices operate on the same 2.4 GHz frequency.

How to Check Wi-Fi Strength on Your Smartphone (Android and iOS)

Smartphones are the most convenient devices for quickly checking a signal, as they are always at hand. However, standard tools Android And iOS They don't show exact dBm values. For this, you'll need third-party apps or hidden menus.

On Android

In most smartphones Android You can see the signal level in dBm without installing additional programs:

1. Open Settings → Wi-Fi.
2. Click on the name of your network (don't connect, just tap on the name).
3. In the window that appears, find the line Signal level or Signal strength — there will be a value in dBm.

If this option is not available, use one of the applications:

• 📱 WiFi Analyzer (from farproc) - shows the signal level, channel load and recommends optimal settings.
• 📊 NetSpot — creates a heat map of indoor Wi-Fi coverage.
• 🔍 WiFi Signal Meter — a minimalistic tool with a real-time signal change graph.

Make sure Wi-Fi is turned on

Disable VPN (may distort results)

Close background applications using the internet

Stay in one point for at least 10 seconds for stable readings-->

On iPhone (iOS)

IN iOS Apple has hidden the dBm display in the standard interface, but there is a workaround via Field Test mode:

1. Open the app Telephone and dial 3001#12345#.
2. Click "Call" - a menu will open Field Test.
3. The value will appear at the top of the screen. RSSI (This is the signal level in dBm). A negative number is normal!
4. To return to the normal signal indicator, press the Done button or restart your phone.

For continuous monitoring, install:

• 📲 AirPort Utility (official app from Apple, shows RSSI in dBm).
• 📈 WiFi SweetSpots — analyzes the signal and suggests the best locations for placing the router.

Checking the Wi-Fi connection on a laptop or PC (Windows, macOS, Linux)

Computers offer more options for analyzing Wi-Fi than smartphones. Windows And macOS You can do without third-party software, and Linux a terminal will be required.

Windows 10 and 11

The easiest way is through command line:

1. Click Win + R, enter cmd and press Enter.
2. Enter the command:

   netsh wlan show interfaces

3. Find the line Signal level - there will be a percentage and a value in dBm (for example, 95% (-48 dBm)).

For detailed analysis, use:

• 🖥️ WiFi Info View (from NirSoft) - shows all connected networks, their channels, width and signal level.
• 📡 inSSIDer — a professional tool for scanning the airwaves and finding free channels.
• 🌡️ Acrylic Wi-Fi — creates graphs of signal and speed changes in real time.

How to save a Wi-Fi network report in Windows?

IN WiFi Info View select File → Save Selected Items (or click Ctrl+S). The report will be saved in the format .txt or .csv with data on all detected networks, including MAC addresses, channels and signal strength.

macOS

On MacBook or iMac hold down the key Option (⌥) and click the Wi-Fi icon in the menu bar. A drop-down list will appear with additional information, including:

• RSSI — signal level in dBm.
• Tx Rate — current data transfer rate.
• Channel — the channel used.

For advanced analysis:

• 🍎 Wireless Diagnostics (built-in utility). Launches via Option + click Wi-Fi → Open Wi-Fi Diagnostics.
• 📊 NetSpot — creates a map of indoor Wi-Fi coverage, indicating “dead zones”.

Linux (Ubuntu, Debian, Fedora)

In the terminal, run the command:

iwconfig wlan0 | grep"Signal level"

Where wlan0 — the name of your Wi-Fi adapter (you can find it out using the command ip a). The result will be in the following format:

Signal level=-58 dBm

For real-time monitoring, install wavemon:

sudo apt install wavemon # for Debian/Ubuntu
sudo dnf install wavemon # for Fedora

Run the utility with the command wavemon - it will show a graph of the signal level, speed and other parameters.

How to check the signal strength directly on the router

If you want to check how well your router "sees" connected devices, you can do so through its web interface. The instructions are universal for most models (TP-Link, ASUS, Keenetic, MikroTik etc.), but the paths to the menu may differ slightly.

1. Connect to the router via cable or Wi-Fi.
2. Open your browser and enter the router's IP address (usually 192.168.0.1, 192.168.1.1 or 192.168.8.1).
3. Enter your login and password (by default it is often admin/admin).
4. Go to the section with a list of connected devices. The names may vary:
   • DHCP → Clients (TP-Link),
   • Local Network → Devices (Keenetic),
   • Wireless → Client List (ASUS).

Find the column Signal Strength or RSSI — there will be values ​​in dBm or percentages.

Some routers (eg. Ubiquiti UniFi) allow you to build heat map of coverage directly in the web interface. To do this:

1. Download the floor plan in format .jpg or .png.
2. Please specify the scale (e.g. 1 pixel = 10 cm).
3. Mark the position of the router and access points.
4. The system will automatically calculate coverage areas taking into account obstacles.

⚠️ Attention: If the list of connected devices displays the signal strength -90 dBm If the signal is below 2.4 GHz, this may indicate that the device is at the edge of the coverage area or is using a suboptimal frequency (for example, 5 GHz through several walls). Try switching to a 2.4 GHz network or moving the router closer.

Wi-Fi coverage mapping apps

If you need to not just measure the signal at one point, but analyze the coverage throughout your entire home or office, specialized programs for constructing heat mapsThey show where the signal weakens and help optimally position the router or extenders.

Top 3 Wi-Fi Mapping Software:

• 🗺️ NetSpot (Windows/macOS) is the easiest solution for beginners. The free version allows you to create a map for two access points. The paid version (PRO) supports unlimited number of networks and report export.
• 📡 Ekahau HeatMapper (Windows) — a professional tool with 3D mapping support. Suitable for offices and large spaces.
• 📱 WiFi SweetSpots (iOS/Android) — a mobile application that creates a map based on a photograph of a room plan.

How to build a coverage map in NetSpot:

1. Download and install the program from official website.
2. Upload a floor plan or draw one by hand.
3. Specify the scale (for example, the distance between two walls).
4. Walk around the room, stopping at key points (near a window, in a corner, behind a wall). The program will record the signal level.
5. Once completed, you will receive a color map where green is a strong signal and red is a weak signal.

Example of a heat map:

⚠️ Attention: When creating a coverage map, keep in mind that metal objects (refrigerators, radiators), mirrors, and aquariums significantly weaken the signal. If unexpected "dead zones" appear on the map, check for such obstacles nearby.

What to do if your Wi-Fi signal is weak

If your measurements show that the signal level in your network is far from ideal (below -70 dBm), try the following steps to improve coverage:

1. Optimize your router's location

• 📍 Place the router in in the center of the room, and not in the corner.
• 🪟 Raise it higher - onto a cabinet or shelf (the signal spreads better from top to bottom).
• 🚫 Keep away from metal surfaces, microwaves and other sources of interference.

2. Change Wi-Fi channel

If neighboring networks are using the same channel, this creates interference. How to choose a clear channel:

1. Use WiFi Analyzer (Android) or inSSIDer (Windows) to scan the air.
2. In the router's web interface, go to Wi-Fi Settings → Channel.
3. Select the channel with the least load (for example, if all your neighbors are on channel 6, switch to channel 1 or 11).

3. Update your router firmware

Manufacturers regularly release updates that improve signal stability and strength. How to update:

1. Download the latest firmware from the manufacturer's website (for example, TP-Link or ASUS).
2. In the router's web interface, find the section System → Software Update.
3. Download the firmware file and wait for the process to complete (do not turn off the router!).

4. Use repeaters or mesh systems

If the router cannot cover the entire area, add:

• 🔄 Repeater - enhances the signal, but may reduce the speed.
• 🕸️ Mesh system (For example, TP-Link Deco, Google Nest WiFi) - several access points operating as a single network.

5. Check the transmit power settings

Some routers allow you to manually adjust signal strength. Find this setting in the web interface. Transmit Power (or Transmission power) and set the value High or 100%.

⚠️ Attention: Increasing the transmit power may cause the router to overheat and shorten its lifespan. If your router becomes excessively hot after changing the settings, return it to the previous setting. Medium.

Common Mistakes When Measuring Wi-Fi Strength

Even experienced users sometimes make mistakes that distort measurement results. Here are the most common ones:

• 📱 Measuring signal in motionThe dBm level should be fixed in a static position (at least 5–10 seconds at one point).
• 🔋 Dead batteryOn smartphones, when the battery is low, the Wi-Fi module may operate in power-saving mode, reducing performance.
• 🌡️ Ignoring temperatureOverheating of the router or device automatically reduces signal strength.
• 📡 Test on one device onlyDifferent devices have different antenna sensitivities. For example, MacBook can show -60 dBm, and the old smartphone in the same place - -75 dBm.
• 🔄 Failure to take frequency into accountThe 5 GHz signal will always be weaker at a distance than the 2.4 GHz signal, even if the router is the same.

Another typical mistake is comparison of dBm and percentagesSome programs show the signal level as a percentage (for example, 75%), but this is not the same as dBm. The percentages are calculated using the device's internal scale and are not standardized. For example, 50% on one laptop can match -60 dBm, and on the other - -70 dBm.

To avoid errors:

• Take measurements on multiple devices.
• Use the same app for all checks.
• Record not only dBm, but also the connection speed (for example, via Speedtest).

FAQ: Answers to Frequently Asked Questions

Is it possible to increase Wi-Fi signal strength without buying a new router?

Yes, try:

• Change the channel to a less busy one.
• Update the router firmware.
• Move the router to another location (for example, closer to the center of the room).
• Disable power saving for the Wi-Fi adapter (in Windows power settings).
• Use homemade signal amplifiers (for example, an antenna made from a chip can - it works as a passive reflector).

If all else fails, consider purchasing an inexpensive repeater (from 1,000 ₽) or a Mesh system.

Why does my phone have 3 Wi-Fi bars, but the speed is low?

The number of "bars" is a conventional indicator and doesn't always reflect the actual signal strength. Possible reasons for low speed despite a "good" indicator:

• High channel load (many neighbors are using the same frequency).
• Speed ​​limitation by the provider (check your tariff).
• DNS problems (try changing DNS to 8.8.8.8 or 1.1.1.1).
• Outdated Wi-Fi standard (for example, your phone only supports 802.11n, and the router operates in mode 802.11ac).

Check the actual signal level in dBm - it may be lower -70 dBm, the indicator shows 3-4 sticks.

What is the minimum signal strength required for online gaming?

For stable, lag-free gaming, we recommend:

• Signal level: not lower than -65 dBm (optimally from -50 to -60 dBm).
• Connection speed: from 10 Mbit/s (For CS:GO, Dota 2) or from 50 Mbps (For Call of Duty: Warzone, Fortnite).
• Ping: below 50 ms (for competitive games like Valorant or League of Legends).

If the signal is weaker -70 dBm, connect to the router via cable or use Powerline adapters.

Why does the Wi-Fi signal get worse at night?

Possible reasons:

• 🌙 Planned work by the provider (usually from 00:00 to 6:00).
• 📡 Changing channel load (at night some neighbors may run torrents or updates, taking up bandwidth).
• 🔋 Energy saving (Some routers automatically reduce signal strength during off-peak hours).
• 🌡️ Router overheating (if it works 24 hours a day without a break).

Check if the signal deteriorates during the day (for example, after WiFi Analyzer (at the same time). If the problem only occurs at night, try rebooting the router before going to bed.

Is it possible to measure signal strength without connecting to the network?

Yes, but this requires special applications that scan all available networks. For example:

• On Android: WiFi Analyzer Shows the signal strength of all visible networks, even if you are not connected to them.
• On Windows: inSSIDer or Acrylic Wi-Fi scan the air and display RSSI for all access points.
• On macOS: Wireless Diagnostics (on the menu Window → Scan).

Please note: Some networks may hide their SSID (name) and will not appear in the scan list.