Sound Intensity, Power and Pressure Levels

Calculate decibel levels for sound power, intensity, and pressure. Understand logarithmic ratios of physical values using reference standards for hearing threshold.

Measurement TypeSignal/ValueReference ValueFormulaLevel (dB)
Sound Power LevelN (W)10⁻¹² WLN = 10 log(N / Nref)=10*LOG10(inputs.sound_power/1e-12)
Sound Intensity LevelI (W/m²)10⁻¹² W/m²LI = 10 log(I / Iref)=10*LOG10(inputs.sound_intensity/1e-12)
Sound Pressure Levelp (Pa)2×10⁻⁵ PaLp = 20 log(p / pref)=20*LOG10(inputs.sound_pressure/2e-5)
General Signal LevelS (Signal Unit)Sref (Signal Unit)L = 10 log(S / Sref)=10*LOG10(inputs.signal/inputs.signal_ref)
Calculator

Inputs

Results

Sound Power Level-- dB
Sound Intensity Level-- dB
Sound Pressure Level-- dB
General Signal Level-- dB

Reference Standards

Sound Power Level (Lp):

  • Reference: 10⁻¹² W (threshold of hearing)
  • Range: 0 dB (barely audible) to ~170 dB (jet aircraft)
  • Formula: Lp = 10 log(N / 10⁻¹²)

Sound Intensity Level (Li):

  • Reference: 10⁻¹² W/m²
  • Formula: Li = 10 log(I / 10⁻¹²)

Sound Pressure Level (Lp):

  • Reference: 2×10⁻⁵ Pa (threshold of hearing)
  • Formula: Lp = 20 log(p / 2×10⁻⁵)
  • Note: Doubling pressure increases level by 6 dB

General Decibel Formula:

  • L = 10 log(S / Sref)
Sound Intensity, Power and Pressure Levels | MEPKit Engineering Tools | MEPKit