What this does
Converts an RSSI reading (in dBm) into a signal quality percentage, computes SNR when a noise floor is given, and estimates distance from an access point using the log-distance path loss model — all clearly labeled as estimates rather than exact measurements, since real RF propagation depends heavily on environment. Entirely in your browser.
Why RSSI numbers look so confusing
RSSI is measured in dBm, a logarithmic scale where less negative is stronger — -50 is a strong signal, -90 is very weak, which trips up anyone expecting bigger numbers to mean better. The percentage and distance figures this tool computes exist specifically to translate that logarithmic scale into something more intuitive to reason about, without losing the underlying measurement.
FAQ
Is the RSSI-to-percentage conversion an official standard?
No — there's no single official standard for converting RSSI (a raw dBm measurement) into a percentage; different operating systems and drivers use slightly different formulas. This tool uses a widely-cited convention (100% at -50dBm or stronger, 0% at -100dBm or weaker, linear in between) that matches what several common WiFi tools have historically used, but treat the percentage as a useful approximation rather than a universal figure.
Why does the distance estimate need a path loss exponent at all?
Radio signals don't weaken at the same rate in every environment — in open space with no obstructions, signal strength drops roughly with the square of distance (exponent 2); indoors, walls and furniture cause it to drop faster, commonly modeled with an exponent of 3 to 4. The same RSSI reading corresponds to a very different actual distance depending on which environment you're in, which is exactly what this exponent adjusts for.
Why is the distance estimate labeled an estimate rather than an exact measurement?
The log-distance path loss model is a simplification of real, highly variable RF propagation — actual signal strength at a given distance is affected by walls, furniture, other radios, multipath reflection, and antenna orientation, none of which this formula accounts for directly. It's useful for a rough sense of distance or for comparing readings, not for precise positioning.
What's a reasonable RSSI for a usable WiFi connection?
Roughly -67dBm or stronger is commonly cited as the threshold for a reliable connection supporting typical applications; -70 to -80dBm often still works but with reduced throughput and more retries; below -80dBm connections become unreliable, and below -90dBm a connection may barely function at all, if it connects.
What's the difference between signal quality and SNR?
Signal quality (the percentage this tool computes) reflects raw signal strength alone. SNR (Signal-to-Noise Ratio) additionally accounts for how much background radio noise exists on the same channel — a strong signal sitting on top of an equally strong noise floor can still perform poorly, which is exactly what a low SNR despite a seemingly fine RSSI would reveal.
Try it yourself
For the full picture of what RSSI, SNR, and dBm actually measure, see WiFi Signal Strength Explained. If the problem is congestion rather than weak signal, WiFi Channel Planner finds a less-contested channel.