Free Space Path Loss Calculator
Computes RF signal attenuation in free space (Friis transmission model). Use this as a baseline for link budget analysis, jammer sizing, and RF sensor range planning.
Inputs
Free Space Path Loss
100.1 dB
At 1.00 km · 2.40 GHz
FSPL vs Distance at 2.40 GHz
| Distance | FSPL (dB) |
|---|---|
| 100 m | 80.1 |
| 500 m | 94.0 |
| 1 km | 100.1 |
| 2 km | 106.1 |
| 5 km | 114.0 |
| 10 km | 120.1 |
Formula
FSPL (dB) = 20·log₁₀(d) + 20·log₁₀(f) − 147.55
where d is in meters, f is in Hz. Assumes isotropic antennas and no environmental losses.