dBm to dBmV Conversion Calculator

This tool converts the Power in dBm to an equivalent voltage level (specified in deciBel relative to 1 mV).

Enter:

  • dBm power value
  • Impedance (default value is 50 ohm but any value can be specified)

Background

To convert dBm (decibels relative to 1 milliwatt) to dBmV (decibels relative to 1 millivolt), we need to understand the relationship between power (in dBm) and voltage (in dBmV).

The conversion requires the characteristic impedance of the system, typically 50 ohms or 75 ohms, because the relationship between power and voltage depends on the impedance.

Formula

PdBmV​ = PdBm ​+ 10*Log10​(Z) + 30

where Z is the impedance

Example Calculations

A value of 1 dBm in a 50 ohm system is equivalent to 48 dBmV.

10 dBm in a 75 ohm system is equivalent to 57 dBmV.

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