Skip to content
ENExplore Calculators

Sound Intensity Level (dB) Calculator

Work out sound intensity level (db) instantly with clear inputs, formula shown and shareable results.

About Sound Intensity Level (dB) Calculator

The decibel scale compresses the enormous range of audible intensities logarithmically: L = 10 log10(I/I0). An intensity of 1 mW/m2 against the 1e-12 reference is 90 dB, a billion times the threshold. Every 10 dB is a tenfold intensity increase but sounds only about twice as loud subjectively.

Formulas

Intensity level

L = 10 log10(I / I0)

Reference

I0 = 1e-12 W/m2, the hearing threshold

Worked example

With the default values below, Sound Intensity Level (dB) Calculator returns Sound Intensity Level of 90.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Sound intensityminimum 0 W/m2
0.001 W/m2
Reference intensityminimum 0 W/m2
0 W/m2

Results

Sound Intensity Level
90.00 dB
Intensity Ratio
1.0000 × 10⁹
Level In Bels
9.0000
How Loud That Is
Hearing protection advisable

Step by step

  1. 1Values used
  2. 2Intensity level
  3. 3Reference
  4. 4Sound Intensity Level= 90.00 dB
  5. 5Intensity Ratio= 1,000,000,000.0000
  6. 6Level In Bels= 9.0000
  7. 7How Loud That Is= Hearing protection advisable

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is 10 dB perceived as twice as loud?

Loudness perception follows roughly a power law with exponent 0.3, so a tenfold intensity change gives about a doubling in judged loudness.

Is dB an absolute unit?

No. It is always a ratio against a stated reference, which is why sound levels are strictly dB re 1e-12 W/m2.

Related Calculators

Sound Intensity Level (dB) Calculator | Calcrivo