Skip to content
Calculation Machine

Sound Intensity Decibel Calculator

Sound level in decibels from intensity or distance.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Sound level
95 dB
Intensity
3.183e-3 W/m²
Distance
5 m

Quick answer

Sound level (dB) = 10 x log10(I / I0), with I0 = 1e-12 W/m^2.

The formula

L = 10 log10(I/I0)

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Source power1 W
  • Distance from source5 m

Result

  • Sound level95 dB
  • Intensity3.183e-3 W/m²
  • Distance5 m

How to use the Sound Intensity Decibel Calculator

  1. 1Enter the acoustic power of the source and the listening distance.
  2. 2The calculator spreads the power over a sphere to get intensity, then converts to decibels.
  3. 3Compare the result against common reference levels (60 dB conversation, 120 dB pain threshold).

Frequently asked questions

Why does doubling distance drop the level by 6 dB?

Intensity falls with the square of distance, and each doubling of intensity is about 3 dB, so distance doubling is about 6 dB.

Is this the same as loudness?

Decibels measure physical intensity; perceived loudness also depends on frequency and human hearing sensitivity.

About this calculator