What Is WiFi Signal Strength?
WiFi signal strength is measured in decibel-milliwatts (dBm). This shows how strong the wireless signal is between your device and your router.
As a rule of thumb:
- -30 dBm = excellent (very close to the router)
- -50 to -60 dBm = strong and reliable
- -67 dBm = minimum for stable streaming and video calls
- -70 dBm or lower = weak, likely to cause issues
The closer the number is to zero, the stronger the signal.
How to Measure WiFi Signal Strength on Your Devices
Use Built-In Device Tools
Most devices show signal strength using bars, but some provide more detail:
- Windows: Open WiFi settings, then Network properties (basic indicator)
- macOS: Hold Option and click the WiFi icon to view dBm values
- iPhone / Android: Signal bars give a rough guide, but apps provide better accuracy
Bars are useful, but they don’t tell the full story, as two bars can still mean very different performance levels.
Use a WiFi Signal Strength App
Apps are the most accurate way to measure WiFi signal strength throughout your home.
Popular options include:
- WiFi Analyser (Android)
- AirPort Utility (iOS – WiFi Scan enabled)
- NetSpot (Windows & macOS)
Walk around your property while monitoring dBm values to spot dead zones and weak areas.
Test Signal Strength vs Real Performance
Signal strength directly affects what you can actually do online.
Weak WiFi often causes:
- Slow loading despite fast broadband
- Buffering on streaming services
- Dropped video calls
- Lag during online gaming
If your speed test is fast near the router but slow in other rooms, the issue is WiFi coverage, not your broadband connection.
Common Causes of Weak WiFi Signal
- Distance from the router
- Thick walls, stone walls or metal structures
- Electrical interference
- Too many devices on one band
- Router placement (e.g. cupboards or floor level)
What to Do If Your Signal Is Weak
- Move your router to a central, elevated position
- Use the 5GHz band for speed (shorter range) and 2.4GHz for coverage
- Consider WiFi extenders or mesh systems for larger homes
- Avoid placing routers near TVs, microwaves or metal objects
Why Measuring WiFi Signal Strength Matters
Measuring WiFi signal strength regularly helps you understand whether connectivity issues are caused by coverage, interference or layout and not your broadband line itself. With the right setup, you can get more reliable performance from your existing connection.
