How to accurately measure Wi-Fi signal strength: from -30 dBm to -90 dBm

A weak Wi-Fi signal is one of the most common causes of slow internet and connection drops when streaming video or playing online games. But how can you tell if the problem is with the signal strength, and not your provider's plan or router settings? Wi-Fi power is measured in decibels-milliwatts (dBm) — a negative value, where -30 dBm - excellent signal, and -90 dBm - practically no communication.

In this article, you'll learn how to check signal strength on any device—from a smartphone to a laptop—what values ​​are considered normal for different tasks (surfing, gaming, 4K video), and what to do if the results are lower than expected. We'll explore built-in operating system tools, specialized apps, and even hidden router features not mentioned in the manuals.

Important: Signal strength and internet speed are two different things. Signal in -60 dBm can provide 100 Mbps, and the signal in -40 dBm — only 10 Mbps if the channel is overloaded with other devices. Therefore, diagnostics always begin with checking the dBm level.

1. What is dBm and what are normal signal values?

Unit of measurement dBm (decibel-milliwatt) shows the signal power relative to 1 milliwatt. The closer the value is to zero (for example, -30 dBm), the stronger the signal. Negative numbers can be confusing: -50 dBm better than -70 dBm, although the number is larger in absolute value.

Here is a generally accepted scale for rating Wi-Fi signal strength:

⚠️ Attention: These values ​​are relevant to the standard Wi-Fi 5 (802.11ac) And Wi-Fi 6 (802.11ax). Outdated routers with 802.11n may show a weaker signal even near the access point due to the lower sensitivity of the antennas.

In practice for stable operation minimum recommended signal level is -67 dBmIf your device's performance is worse, consider improving coverage (using repeaters or mesh systems) or changing the Wi-Fi channel.

2. How to check Wi-Fi strength on Windows 10/11 without software

In operating systems Windows There are hidden tools for displaying signal levels in dBm. You don't need to install third-party software—a few clicks or a command in Command line.

Method 1: Via the taskbar (quick method)

1. Tap the Wi-Fi icon in the lower right corner of the screen (next to the clock).
2. In the list of available networks, find yours and hover your cursor over it – a pop-up tip with the signal strength percentage will appear. But this is not dBm!
3. To see the exact data, right-click on the Wi-Fi icon → Open Network & Internet Settings.
4. Go to Wi-Fi → Manage known networks, select your network and click Properties.
5. Scroll down to the block Properties - there will be a line Signal level with a value in dBm.

Method 2: Via Command Line (exact details)

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

   netsh wlan show interfaces

3. Find the line Signal — there will be a value in percentage And in dBm (for example, 98% (Very good) -42 dBm).

Check if you are connected to Wi-Fi|Run Command Prompt as Administrator|Update your Wi-Fi adapter drivers|Restart your router-->

⚠️ Attention: In some laptops (especially with adapters) Realtek) the team can show N/A instead of dBm. In this case, use device Manager to update drivers or proceed to the method with third-party utilities.

3. Checking the signal on macOS: hidden features

On computers MacBook And iMac You can check your Wi-Fi signal strength without installing any additional software, but the method is somewhat hidden. Apple doesn't display dBm in the standard interface, but this data is available through the system report.

Instructions for macOS Ventura and later:

1. Hold down the key Option (⌥) and click on the Wi-Fi icon in the menu bar.
2. Additional information will appear in the drop-down list, including:
   • 📶 RSSI - this is the signal level in dBm (for example, -58 dBm).
   • 🔄 Tx Rate — current data transfer rate.
   • 📡 Channel - Wi-Fi channel (useful for interference diagnostics).

For older versions of macOS (before Monterey):

1. Open the app Wireless Diagnostics (find through Spotlight on request "Wireless diagnostics").
2. In the menu, select Window → Utilities (or Window → Utilities (in Russian).
3. In the tab Wi-Fi Scan click Scan Now — a list of networks with signal levels will appear.

⚠️ Attention: On Mac with chips Apple Silicon (M1/M2/M3) report Wireless Diagnostics may not show dBm for some networks. In this case, use the app NetSpot (free version available in App Store).

4. Mobile devices: Android and iOS

Checking the Wi-Fi signal strength on smartphones and tablets is more difficult—manufacturers often hide technical specifications. But there are workarounds.

On Android:

• 📱 Hidden engineering menu (does not work on all models):
  1. Open the app Telephone and enter ##4636##.
  2. Select Wi-Fi Information (or Wi-Fi information).
  3. Find the line Wi-Fi signal strength — value in dBm.
Which smartphones does the code work on? ##4636##?

On most Samsung, Xiaomi, Google Pixel, and some Huawei devices. On smartphones running ColorOS (Oppo, Realme) and MIUI (Xiaomi), you may need to unlock the engineering menu via ADB.

4. 📊 Analyzer applications:
   • WiFi Analyzer (from farproc) - shows the signal in real time.
   • NetSpot — creates a heat map of the coverage.
   • Fing - analyzes the network and displays the dBm level.

On iPhone and iPad:

• 🍎 Secret trick with signal stripes:
  1. Open Settings → Wi-Fi.
  2. Click on the icon i near your network.
  3. Field Signal level will show the number of "bars" (1-3), but not dBm. To see the exact data, you need to use Shortcuts or third-party applications.
5. 🛠️ iOS apps:
   • AirPort Utility (official from Apple, but requires enabling in settings).
   • WiFi SweetSpots — shows dBm and recommends the best location for the router.

5. Checking the signal through the router: web interface and Telnet

If you need to know the signal level not on the client device, but directly on the source - the router - you can do this through its web interface or Telnet/SSHThis method is useful for diagnosing interference from neighboring networks or checking the coverage of mesh systems.

Via the web interface (for example TP-Link, ASUS, Keenetic):

1. Open your browser and enter the router's IP address (usually 192.168.0.1 or 192.168.1.1).
2. Log in (default logins: admin/admin or see the router sticker).
3. Go to section:
   • For TP-Link: Wireless Mode → Statistics.
   • For ASUS: Network Map → Clients (point at device).
   • For Keenetic: System Monitor → Wireless Network.

Via Telnet/SSH (for advanced users):

Some routers (for example, on firmware OpenWRT or DD-WRT) allow you to receive signal data via the command line. Connect via SSH and enter:

iwinfo wlan0 assoclist

or

iw dev wlan0 station dump

Find the line in the output signal or signal avg — is the average signal level in dBm for connected devices.

6. Specialized programs for Wi-Fi analysis

Professional utilities are used for in-depth network diagnostics (searching for interference, optimal channels, and creating heat maps). They show not only the signal strength but also airtime congestion, neighboring networks, and even recommend router settings.

Top 5 programs for PC and mobile devices:

⚠️ Attention: Free versions of programs (for example, NetSpot Free) can limit the number of scans or hide advanced data. This is sufficient for a one-time scan, but professional network setup will require a paid license.

How to use inSSIDer to analyze the signal:

• 📊 Launch the program and wait for the network scan.
• Please pay attention to the columns:
  • SSID — network name.
  • RSSI — signal level in dBm.
  • Channel — channel (if there are several networks on one channel, there will be interference).
  • Max Rate — maximum connection speed.
• 🔍 If your network shows low RSSI (worse than -70 dBm), try changing the channel in your router settings to a less crowded one.

• 📍 Move the router:
  • Place it in the center of your apartment/office, raise it to a height of 1–1.5 meters (not to the floor!).
  • Keep away from metal objects, mirrors and household appliances (microwaves, refrigerators).
• 🔄 Change Wi-Fi channel:
  • In the router settings (192.168.0.1) find the section Wireless Network → Channel.
  • Select the channel that your neighbors use the least (for example, 1, 6, or 11 for 2.4 GHz).
• 📶 Switch to 5 GHz:
  • The 5 GHz network has a smaller coverage area, but less interference and higher speed.
  • In your router settings, activate a separate network for 5 GHz (for example, MyWiFi_5G).
• 🔌 Update your router firmware:
  • Go to the router's web interface and check the section Software update.
  • New firmware often improves signal stability and supports modern standards (Wi-Fi 6).
• 🛠️ Use a repeater or mesh system:
  • Repeater (TP-Link RE605, Xiaomi Wi-Fi Repeater) will strengthen the signal in remote rooms.
  • Mesh system (Google Nest Wi-Fi, ASUS ZenWiFi) will ensure smooth roaming without interruptions.