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Spherical Wave Intensity (Inverse-Square) Calculator

I = P / (4π · r²) — uniform spherical radiator.

Compute the wave-power intensity at distance r from an isotropic point source emitting total power P: I = P / (4π · r²). Reports intensity in W/m² and the equivalent sound pressure level in dB SPL referenced to 10⁻¹² W/m².

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

W
m

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

I = P / (4π · r²)

In depth

Compute the wave-power intensity at distance r from an isotropic point source emitting total power P: I = P / (4π · r²). Reports intensity in W/m² and the equivalent sound pressure level in dB SPL referenced to 10⁻¹² W/m².