How to use it
- Enter a positive frequency and select MHz or GHz.
- Enter a positive path distance.
- Calculate the ideal path loss in decibels.
Free Space Path Loss Calculator
Estimate theoretical free-space attenuation for a frequency and unobstructed distance.
Important: This calculator is for educational and estimation purposes only. It is not telecom engineering, safety, regulatory, or compliance advice. Always consult qualified professionals and local regulations for real-world deployments.
About the Free Space Path Loss Calculator
FSPL describes ideal geometric spreading loss between two points in unobstructed free space.
Formula
With distance in kilometers and frequency in MHz, FSPL is 32.44 + 20 log10(distance) + 20 log10(frequency).
Example
At 100 MHz over 1 km, the ideal free-space path loss is about 72.44 dB.
Notes
This free-space model excludes terrain, buildings, reflections, weather, polarization, antenna patterns and regulatory constraints.