About the Decibel Calculator

The decibel is a logarithmic measure of sound intensity relative to a reference. When two sources play together, their intensities (10^(L/10)) add, and the combined level is L = 10·log₁₀(10^(L1/10) + 10^(L2/10)). Two identical 60 dB sources therefore produce 63 dB, not 120 dB.

Reading Intensity Ratios

Each 3 dB is a doubling of intensity; each 10 dB is a tenfold increase and is perceived as roughly twice as loud. A level difference of 3 dB is barely noticeable in practice; 10 dB is clearly subjectively louder. The ratio column quantifies exactly how much more intense one source is than the other.