Free Space Path Loss Calculator
Use frequency in MHz and distance in km with the free-space FSPL formula. This is not a link-availability prediction.
Calculate FSPL
A QUICK WALKTHROUGH
How to use this tool
- Enter frequency in MHz and distance in km.
- Calculate the free-space path loss with the displayed formula.
- Treat the result as an idealized estimate and assess the real link separately.
Ideal free-space model
FSPL is calculated from user-entered frequency and distance only. The estimate excludes obstacles, terrain, multipath, fading, atmospheric effects, antenna gain, polarization, feeder or cable loss, connector loss, transmit power, receiver sensitivity, and other link-budget terms.
Units and limits
Use positive finite frequency in MHz and distance in km. Converting units incorrectly changes the result. This number does not establish link availability, coverage, safety, compliance, or performance.
Local browser calculation
Inputs and calculations stay in this browser. No radio, network, or external service is contacted.
GOOD TO KNOW
Common questions
Does this predict whether a link will work?
No. It is only the ideal free-space path-loss term; a complete link budget and real-world conditions are separate.
Which units are used?
Enter frequency in MHz and distance in km.
Does it include obstacles or multipath?
No. Those effects and other losses are outside this calculator.