What is it?
The Decibel Calculator does three jobs. Choose what I want to do.
Who is it for?
Sound engineers, event organisers, students, and anyone checking noise at work or events.
Three tasks
- Add sound levels together: enter Sound levels (dB) to get the Combined level. Decibels add on a log scale: two equal sources are 3 dB louder, not double.
- Find the level farther away: enter the Level measured, At distance and New distance. Outdoors, sound from a small source drops about 6 dB each time the distance doubles (inverse square law).
- Turn a power or voltage ratio into decibels: enter the Reference value and Measured value. Power: dB = 10 log(P2/P1). Voltage, current or sound pressure: dB = 20 log(V2/V1).
How loud is loud?
- Quiet room 30–40 dB, normal talk 60 dB, busy traffic 80 dB, pressure horn or DJ speakers 100–110 dB.
- Long exposure above 85 dB can damage hearing. Every +3 dB halves the safe listening time.
- A 10 dB rise sounds about twice as loud to our ears.
Indoors, walls reflect sound, so levels drop less with distance than the outdoor rule says.
Worked example
Two speakers at 90 dB together make 93 dB; at twice the distance outdoors, 87 dB.
Errors and how to fix them
- “Type the levels to add, e.g. 80 80”
- “Enter the first distance / the new distance (more than 0)”
Open the tool: Decibel Calculator
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.