Path Loss Calculator
Enter the known values and run the calculation.
Overview
Estimate free-space path loss for link-budget planning and first-pass propagation checks.
Use this tool to estimate free-space path loss from frequency and distance. It gives you the standard first-pass number used in RF link budgets.
Use it when checking whether antenna gain, transmit power, cable loss, and receiver sensitivity are even in the right range before moving to a fuller propagation model.
The math and how it's used
The free-space path loss relationship used here is FSPL(dB) = 32.44 + 20 log10(distance in km) + 20 log10(frequency in MHz).
The calculator also reports wavelength so you can connect the link-budget number back to antenna scale and physical layout.
This is the textbook free-space path-loss number engineers use to get the first link-budget cut on paper.
It is useful for range intuition and relative comparisons, but once antennas are near the ground, inside structures, or looking through weather and clutter, the real path can diverge a lot from free-space loss.
Limits of the result
Free-space path loss assumes clear line of sight with no clutter, obstruction, polarization mismatch, or multipath penalty.
That makes it the right first number for planning, but not the last number for a real fielded system.