This tool calculates the dB (deciBel) equivalent of a voltage ratio.

Enter

- Input Voltage (Vin)
- Input Impedance (Rin)
- Output Voltages (Vout)
- Output Impedance (Rout)

## Formula

**PdB = 10*Log _{10}((V_{out}^{2}/R_{out})/(V_{in}^{2}/R_{in}))**

## Example Calculation

If the output and input voltages are 2 V and 1 V, respectively, the dB equivalent of the ratio is 6 dB. This assumes the input and output impedance are the same.

When the output voltage is greater than the input, the dB value is positive (+) and it represents a gain.

When the output voltage is smaller than input, the dB value is negative (-) there’s a loss or attenuation.