Wi-Fi Signal Strength & Path Loss

Convert a Wi-Fi signal in dBm to a quality rating and estimate the signal at a distance using free-space path loss, free online.

Measured signal (dBm, negative)

Router transmit power + antenna gain (dBm)

Frequency (MHz)

Distance from the router (m)

Walls in between (≈ 5 dB each)

About this calculator

Signal quality is estimated from RSSI: −50 dBm or better is excellent, −60 good, −70 fair (enough for streaming), −80 poor, −90 unusable. Free-space path loss FSPL = 20·log₁₀(d) + 20·log₁₀(f) + 32.44 (d in km, f in MHz); walls add 3–15 dB each. 5 GHz loses more than 2.4 GHz.