Estimate WiFi access point coverage radius and area based on power and environment.
WiFi range is estimated using the free-space path loss (FSPL) model, which relates signal loss to distance and frequency: FSPL(dB) = 20·log10(distance_km) + 20·log10(freq_MHz) + 32.44. Rearranging for distance, given the maximum path loss the link budget allows (transmit power minus receiver sensitivity minus any wall/obstruction attenuation), yields the theoretical range. Higher frequencies (5/6 GHz) attenuate faster over distance than 2.4 GHz, which is why 2.4 GHz networks reach further but 5/6 GHz offer more capacity and less interference at closer range. Real-world range is usually shorter than this free-space estimate due to additional obstructions, multipath, and interference not captured by this simplified model.
Free-space path loss
FSPL(dB) = 20·log10(distance_km) + 20·log10(freq_MHz) + 32.44
Maximum range from link budget
range = 10^((tx_power − rx_sensitivity − wall_loss − 20log10(f) − 32.44) / 20)
Higher frequency signals attenuate faster over distance and are more easily blocked by obstacles, which is a direct consequence of the FSPL formula's 20·log10(freq_MHz) term — doubling frequency from 2.4 to roughly 5 GHz adds about 6.3 dB of extra path loss at the same distance.
The free-space model assumes an unobstructed line-of-sight path with no reflections, interference, or absorption. Real environments have walls, furniture, other WiFi networks sharing spectrum, and multipath fading, all of which reduce effective range below the theoretical free-space number.
Most consumer WiFi clients need roughly -70 dBm or stronger for a solid, high-throughput connection, though they may still connect (at lower speeds) down to around -85 to -90 dBm. Video calls and high-bandwidth applications generally want -65 dBm or better.
Each additional AP adds its own coverage cell, so total coverage area scales with AP count assuming cells don't need to overlap much — but AP placement, overlap for roaming, and interference between APs on the same channel all matter in real deployments, which this simplified model doesn't capture.