📈 dB Gain Calculator
Enter input and output power (or voltage) to calculate gain in decibels (dB).
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What is dB gain?
Decibels (dB) express a ratio between two power or voltage/amplitude levels on a logarithmic scale, making it easier to work with the huge ranges common in audio, RF, and electronics.
The formula
For power ratios, Gain (dB) = 10 × log10(Pout ÷ Pin). For voltage, current, or other amplitude ratios (where power is proportional to the square of the quantity), Gain (dB) = 20 × log10(Vout ÷ Vin). Select the correct signal type since using the wrong formula will give a result twice as large (or half) as it should be.
A positive dB value indicates gain (amplification); a negative value indicates loss (attenuation). This calculator is for general electronics and audio education.
Last reviewed August 2026