dBm/Hz to nV/SQRT Hz Calculator

This tool converts dBm per Hz to nV per root(Hz) or nV/√(Hz).

nV/√(Hz) to dBm/Hz


Spectrum and Signal Analyzers provide signal output levels in dBm. Units for Noise specifications are usually nV/sqrt(Hz).


nv/(√Hz) = √((10dBm/Hz/10)*Z*0.001)

Example Use

A spectrum analyzer provides amplitude measurement in terms of dBm with an associated resolution bandwidth. Use this calculator to find the dBm value in a 1 Hz RBW or dBm/Hz.

dBm/Hz can be converted to nV/√Hz using the calculator on this page.

As an example, -150 dBm/Hz converts to 7.07 nV/√Hz.

In this calculation the default impedance value of 50 ohm is used. You can also change the value of the impedance.

As well the units can be changed to any of the following:

  • nV/√Hz
  • uV/√Hz
  • mV/√Hz
  • V/√Hz


[1] In this post, the author has derived the result taking readings from a spectrum analyzer. The results show that -156 dBm/Hz = 3.544 nV/Root Hz – same as what you get when you use the calculator.