Enter the impedance (ohms) and the dBm into the calculator to determine the RMS Voltage from dBm.

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## RMS Voltage from dBm Formula

The following formula is used to calculate the RMS Voltage from dBm.

**Vrms = SQRT( Z/1000) * 10 ^ (dBm/20)**

Variables:

- Where Vrms is the RMS Voltage from dBm (volts)
- Z is the impedance (ohms)
- dBm is the dBm

## How to Calculate RMS Voltage from dBm?

The following two example problems outline how to calculate the RMS Voltage from dBm.

**Example Problem #1:**

- First, determine the impedance (ohms). In this example, the impedance (ohms) is measured to be 5000.
- Next, determine the dBm. For this problem, the dBm is calculated to be 30.
- Finally, calculate the RMS Voltage from dBm using the formula above:

Vrms = SQRT( Z/1000) * 10 ^ (dBm/20)

Inserting the values from above and solving the equation with the imputed values gives:

Vrms = SQRT( 5000/1000) * 10 ^ (30/20) = 70.71 (volts)

**Example Problem #2: **

Using the same process as example problem 1, we first define the variables outlined by the formula. In this case, the values are:

impedance (ohms) = 6000

dBm = 20

Entering these values into the formula or calculator above gives us::

Vrms = SQRT( 6000/1000) * 10 ^ (20/20) = 24.494 (volts)