Enter the total speaker power (watts) and the total speaker resistance (ohms) into the calculator to determine the Speaker Voltage. 

Speaker Voltage Formula

The following formula is used to calculate the Speaker Voltage. 

V = SQRT ( P*R)


  • Where V is the Speaker Voltage (volts)
  • P is the total speaker power (watts) 
  • R is the total speaker resistance (ohms) 

To calculate a speaker voltage, multiply the speaker power by the speaker resistance, then take the square root of the result.

How to Calculate Speaker Voltage?

The following two example problems outline how to calculate the Speaker Voltage.

Example Problem #1:

  1. First, determine the total speaker power (watts). In this example, the total speaker power (watts) is measured to be 50.
  2. Next, determine the total speaker resistance (ohms). For this problem, the total speaker resistance (ohms) is calculated to be 20.
  3. Finally, calculate the Speaker Voltage using the formula above: 

V = SQRT ( P*R)

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

V = SQRT ( 50*20) = 10 (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:

total speaker power (watts) = 25

total speaker resistance (ohms) = 25

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

V = SQRT ( 25*25) = 25 (volts)