Decibel addition calculator

Combined sound level of several noise sources.

Calculating…

How it's calculated

L_total = 10 × log10( Σ 10^(Lᵢ/10) )

Decibels don't add normally: two equal sources are 3 dB louder than one, and a source 10 dB quieter than another adds almost nothing. That is why quietening the loudest machine gives by far the biggest improvement.