Online Tool Store
Wi-Fi Signal Interpreter
Enter RSSI and noise floor to get signal quality, SNR, and margin above the VoIP/video reliability threshold, with band-specific notes. In your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
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- Signal quality
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- SNR
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- Margin above VoIP/video minimum
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How the Wi-Fi Signal Interpreter works
- Read the RSSI from your device's Wi-Fi details; it is always a negative number.
- Pick the band you're connected on, and add the noise floor if your tool reports it, since signal alone does not predict throughput.
- Check the signal-quality rating, SNR, and margin above the VoIP/video reliability threshold before moving the router or adding a second access point.
The method
dBm is logarithmic, so every 3 dB is a doubling or halving of power, and what determines throughput is the margin between signal and noise, not the signal alone.
SNR = RSSI - noise floor; -67 dBm against -95 dBm = 28 dB
-67 is roughly twice the power of -70 and eight times -76 — which is why small dBm changes matter far more than they look.
FAQ
What is a good Wi-Fi signal?
Better than -60 dBm is strong, -60 to -70 is usable for most things, below -75 is unreliable. But an SNR under about 20 dB will disappoint even with a strong signal.
Why is 5 GHz faster but weaker?
Higher frequencies carry more data and pass through walls less well. 5 GHz wins in the same room and loses two rooms away — which is why band steering exists.
My signal is strong but the connection is slow. Why?
Usually interference or congestion rather than distance. A crowded channel raises the noise floor, cutting SNR while RSSI looks fine.
What does the "margin above VoIP/video minimum" figure mean?
-67 dBm is a widely used planning threshold for reliable, timely delivery of real-time traffic like voice and video calls (below it, best-effort traffic like email and web browsing is still fine down to about -70 dBm). The margin is simply your RSSI minus -67 — positive means headroom, negative means you are below that threshold.
Do I need to enter a noise floor?
No — RSSI alone still gives you the signal-quality reading and VoIP margin. Add the noise floor if your Wi-Fi tool reports it to also see SNR, which is the number that actually predicts whether a strong-looking signal will perform well.
How we compare
| Feature | Online Tool Store | A terminal utility | thehomeserverblog RSSI calculator |
|---|---|---|---|
| Signal-to-noise interpretation | ✓ | ✗ | ✓ |
| Band-specific expectations | ✓ | ✗ | ✓ |
| Margin above a real-time-traffic threshold | ✓ | ✗ | ✓ |
| No app install | ✓ | ✓ | ✓ |
| Explains the dB scale | ✓ | ✗ | Some reference tables |
Wi-Fi Signal Interpreter focuses on SNR rather than bars, because a strong signal on a noisy channel is the most common cause of an inexplicably slow link.