Sound Level Converter
Convert between decibels (dB), nepers (Np), and bels (B) for sound and signal levels.
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How to use this calculator
- 1
Enter the sound level value you want to convert.
- 2
Select the unit you are converting from (e.g. decibels).
- 3
Select the target unit (e.g. nepers).
- 4
The result appears instantly.
Frequently asked questions
What is a decibel?
A decibel (dB) is a logarithmic unit used to express the ratio of a value to a reference value — most commonly for sound pressure or signal power. Every 10 dB increase represents a 10× increase in power, or roughly a doubling in perceived loudness.
How loud is 85 dB?
At 85 dB, prolonged exposure can cause hearing damage. Common references: 0 dB = threshold of hearing, 30 dB = quiet library, 60 dB = normal conversation, 85 dB = heavy traffic, 110 dB = rock concert, 130 dB = threshold of pain.
What is a neper?
A neper (Np) is a logarithmic unit using the natural logarithm (base e), while decibels use base 10. Nepers are used in telecommunications and physics. 1 Np ≈ 8.686 dB.
What is the difference between dB and dBA?
dBA (A-weighted decibels) applies a frequency filter that accounts for how the human ear perceives loudness — quieter at low and very high frequencies. Standard dB measurements do not apply this weighting. Noise regulations typically use dBA.
Sound level and decibel conversion
The decibel scale
The decibel scale is logarithmic, not linear. A 10 dB increase represents 10× the acoustic power. A 3 dB increase represents roughly double the power. Perceived loudness doubles approximately every 10 dB. This is why 120 dB (jet engine) is not twice as loud as 60 dB (conversation) — it is a million times more powerful.
Common sound levels
0 dB: hearing threshold | 10 dB: rustling leaves | 30 dB: whisper | 60 dB: normal conversation | 70 dB: vacuum cleaner | 85 dB: heavy traffic (damage risk over 8 hrs) | 100 dB: motorcycle | 120 dB: concert/jet takeoff | 140 dB: gunshot.
dB in electronics and audio
In audio engineering, dBu and dBV express signal levels relative to reference voltages. dBm measures power relative to 1 milliwatt. Amplifier gain is measured in dB. Speaker sensitivity is rated in dB/W/m. Understanding dB is essential for audio system design.
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