TheCircuitDogSignals & RF
Decibel Gain and Loss Calculator
Convert a positive voltage or power ratio into decibels. Select the right formula for what you are comparing.
Enter the values above and select Calculate result.
Formula
dBpower = 10 log₁₀(P₂/P₁); dBvoltage = 20 log₁₀(V₂/V₁)
Worked example
A voltage gain of 2 is approximately +6.02 dB; a power ratio of 2 is approximately +3.01 dB.
Engineering notes
When inferring power from voltage ratios, assume equal input/output impedances. The decibel is a ratio, not an absolute unit by itself.
Always compare calculated values with the actual component datasheet, tolerance stack-up, operating temperature and circuit conditions before applying them to hardware.