dBm to dBuV/m Calculator (with Examples)


The calculator converts from radiated power (EIRP) at the output of the transmitter in dBm to the electric field strength* dBµV/m (deciBels micro-volt per meter).

*Electric Field Strength and Electric Field Intensity refer to the same thing

Typically this measurement is made at 3 meters for the purposes of FCC testing. However you can specify any distance in the calculator.




???? dBuV/m to dBm

Example Application

Use this calculator to determine if you will pass the FCC limit test by making a measurement of the transmit power (EIRP) at the RF IN/OUT port of your device.

Let’s say for example you want to certify your receiver product. Here are the steps you would use to find the field strength:

  • Connect the RF input port to a spectrum analyzer and make a measurement at a desired frequency.
  • Measure the signal power at this frequency (in dBm).
  • Next use this calculator to find the EIRP (in dBm) taking the antenna gain into consideration.
  • Use the EIRP in the calculator on this page and it will give the Field strength in dBuV/m at any specified distance

Example Calculations

For an EIRP of -10 dBm, the field strength at 3 meters is calculated to be 85.2 dBuV/m.

The dBuV/m to dBm tool provides the reverse calculation. For example if the FCC limit is specified to be 55 dBuV/m at a 3m distance, then the maximum EIRP is not to exceed -40.2 dBm.

???? Note that there is a frequency dependence to this limit (i.e. the field intensity limit will vary with frequency) so the EIRP should be taken account based on this.

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