Maker & Reference
Decibel (dB) Calculator
Decibels are logarithmic — 3 dB = 2× power, 10 dB = 10× power, 20 dB = 10× voltage. Calculator for audio, RF, and electrical.
Result
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- Formula
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- Common reference
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- Inverse
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FAQ
Why 10× for power, 20× for voltage? +
Power scales as voltage squared. Doubling voltage = quadrupling power = +6 dB. The 20× formula keeps the same answer as the 10× power version.
Common dB references? +
0 dB = no change. +3 dB = 2× power. -3 dB = half power. +10 dB = 10× louder (perceptually 2× loud).