Decibel Calculator
Calculate the decibel (dB) difference between two power or intensity levels, or convert dB to intensity ratio.
Decibel Result
Decibels (dB) measure the ratio between two power or intensity levels on a logarithmic scale.
Power-based formula:
dB = 10 × log₁₀(P₁ / P₂)
Amplitude/voltage-based formula:
dB = 20 × log₁₀(V₁ / V₂)
Reverse (dB to ratio):
Power Ratio = 10^(dB / 10)Amplitude Ratio = 10^(dB / 20)
Common dB levels (sound):
- 0 dB — Threshold of hearing
- 30 dB — Whisper
- 60 dB — Normal conversation
- 80 dB — Vacuum cleaner
- 90 dB — Lawn mower (hearing damage with prolonged exposure)
- 110 dB — Rock concert
- 130 dB — Threshold of pain
- 140 dB — Jet engine at 30 m
Key insights:
- Every +3 dB ≈ doubling of power
- Every +6 dB ≈ doubling of amplitude/voltage
- Every +10 dB ≈ perceived doubling of loudness
- dB scale is logarithmic: 100 dB is 10 billion times the intensity of 0 dB