Use this calculator to convert from Volt RMS to Power in dBm.

RMS means **root-mean-square** value or** V _{RMS}**

The default impedance is 50 ohm. It can be changed to any value.

**Formula**

**P _{dBm} = 10*log10((V_{RMS})^{2} /Z) + 30**

**Example Calculation**

For V_{RMS} = 1 Volt and impedance (Z) = 50 ohm, the power is 13 dBm.

If instead you would like to convert from **V _{peak-peak} to dBm**, use this calculator instead.