Enter the circuit voltage (volts) and the equivalent resistance (ohms) into the calculator to determine the Power From Resistance. 

Power From Resistance Formula

The following formula is used to calculate the Power From Resistance. 

P = V^2/ Re
  • Where P is the Power From Resistance (watts)
  • V is the circuit voltage (volts) 
  • Re is the equivalent resistance (ohms) 

To calculate power from resistance, square the circuit voltage, then divide by the equivalent resistance.

How to Calculate Power From Resistance?

The following two example problems outline how to calculate the Power From Resistance.

Example Problem #1:

  1. First, determine the circuit voltage (volts). In this example, the circuit voltage (volts) is measured to be 12.
  2. Next, determine the equivalent resistance (ohms). For this problem, the equivalent resistance (ohms) is calculated to be 5.
  3. Finally, calculate the Power From Resistance using the formula above: 

P = V^2/ Re

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

P = 12^2/ 5 = 28.8 (watts)

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:

circuit voltage (volts) = 4

equivalent resistance (ohms) = 2

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

P = 16^2/ 2 = 8 (watts)