Decibel Calculator
Intensity to dB, and what that actually sounds like.
Work out Decibel. Intensity to dB, and what that actually sounds like. Free, with no account and nothing to download.
Scientific notation works. Threshold of hearing is 1e-12, conversation about 1e-6.
Sound intensity level
60 dB
Loud but safe — traffic, a vacuum cleaner
The decibel scale is logarithmic, which is why the numbers stay small across a range of intensities spanning twelve orders of magnitude. Every +10 dB is ten times the physical intensity. But perceived loudness roughly doubles every 10 dB, not tenfold. That gap between physics and perception is why halving a machine's acoustic power — a 3 dB drop — is barely noticeable, and why noise control is so unrewarding: you have to remove 90% of the energy to sound half as loud. Because it is a ratio scale, decibels do not add. Two 60 dB sources together give 63 dB, not 120.
How the Decibel Calculator works
Convert sound intensity to a decibel level, with a plain-language comparison and the perceived loudness. Physical intensity and perceived loudness diverge sharply on this scale, which is why noise control is so unrewarding.
Also known as: sound intensity level calculator · db calculator · sound intensity to decibels · how loud is 90 db
Frequently asked questions
How do I calculate decibels?
dB = 10·log₁₀(I/I₀), with I₀ at 10⁻¹² W/m² — the threshold of human hearing. Conversation at 10⁻⁶ W/m² comes out at 60 dB.
Is 10 dB louder ten times as loud?
It is ten times the physical intensity but only about twice as loud to the ear. That gap is why halving a machine's acoustic power, a 3 dB drop, is barely noticeable.
Do decibels add?
No — it is a ratio scale. Two 60 dB sources together give 63 dB, not 120. Doubling the number of identical sources always adds 3 dB.
At what level does hearing damage start?
Sustained exposure above about 85 dB carries risk, and above 120 dB damage can happen within minutes. The scale being logarithmic hides how enormous those intensity differences are.
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