Enter the voltage and current into the calculator to determine the resistance of a motor. This calculator uses Ohm’s Law to evaluate the resistance.

Motor Resistance Formula

The following formula is used to calculate the resistance of a motor:

R = V / I


  • R is the resistance of the motor (Ohms, Ω)
  • V is the voltage across the motor (Volts, V)
  • I is the current flowing through the motor (Amperes, A)

To calculate the resistance of a motor, divide the voltage across the motor by the current flowing through it.

What is Motor Resistance?

Motor resistance is the opposition that the motor presents to the flow of electric current. It is a crucial parameter that affects the performance and efficiency of the motor. A higher resistance generally means that the motor will draw less current for a given voltage, which can lead to reduced performance but potentially increased efficiency. Conversely, a lower resistance allows more current to flow, which can increase performance but may lead to higher energy consumption and heat generation.

How to Calculate Motor Resistance?

The following steps outline how to calculate the Motor Resistance.

  1. First, measure the voltage across the motor (V) in volts.
  2. Next, measure the current flowing through the motor (I) in amperes.
  3. Use the formula from above: R = V / I.
  4. Finally, calculate the Motor Resistance (R) in ohms.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Voltage across the motor (V) = 24 volts

Current flowing through the motor (I) = 2 amperes