Sound Intensity Level Calculator

About this calculator

This calculator converts an acoustic intensity I (in watts per square meter) into a sound intensity level in decibels using L = 10·log₁₀(I/I₀), where I₀ = 10⁻¹² W/m² is the standard reference intensity, approximately the threshold of human hearing at 1 kHz. Because decibels are logarithmic, a 10 dB increase corresponds to a 10-fold increase in intensity but is perceived as roughly a doubling of loudness.

Acoustic engineers, audiologists, and occupational health and safety professionals use this to assess noise exposure against workplace limits (e.g., OSHA's 85-90 dB thresholds), while audio and architectural acoustics students use it to relate raw physical intensity to the decibel scale used on sound level meters. Enter the sound intensity in W/m² to get the decibel level.