Free Space Path Loss Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserIntermediate
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the distance (km) and frequency (MHz).
- Read the path loss in dB.
How it works
FSPL (dB) = 20·log₁₀(distance km) + 20·log₁₀(frequency MHz) + 32.45.
Worked example
10 km at 2400 MHz. ≈ 120 dB.
Common mistakes
- Treating it as total loss — real links also lose to obstacles, rain and foliage.
- Mixing up MHz and GHz.
Frequently asked questions
What is free-space path loss?
The signal weakening from spreading out over distance in clear line-of-sight — the best case for a radio link.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.