Inverse Square Law Calculator
Intensity scales as 1/r² from a point source in free space.
Instructions
1
Enter known intensity and distance
Provide intensity at r₁ and both distances r₁ and r₂ (consistent units).
Formula
I₂ = I₁ (r₁² / r₂²)
Valid for isotropic point sources in free space. Real systems may deviate due to absorption or directivity.
Common Questions
Does this apply to sound and light?
Yes, in ideal conditions. Absorption and reflections can change the fall-off.
What about directional sources?
Directional antennas or speakers require beam pattern considerations; inverse square is a baseline.