Ohm’s Law Calculator

Ohm’s Law Calculator

Ohm’s Law can be applied to the electrical behavior of conductors and insulation. This calculator is designed to help you learn more about the interaction between voltage, current, and resistance.

Voltage (V)  V = I x R

Current (I)  I = V / R

Resistance (R)  R = V / I

Calculation Result

____ will cause
____ to flow through
(The power dissapated in the resistance is ____)

Previous Calculations



  1. Enter any two of three values (V, I, and R)
  2. Click “Calculate”
  3. The third value will be displayed in the Calculation Result section

Note: This general-purpose calculator can generate combinations of voltage and current that are not practical in normal cable testing applications. If the calculation shows voltages or currents out of the specified range for a cable tester, then you know the tester doesn’t measure the resistance with the current or voltage you’ve selected.


Ohm’s Law describes one possible relationship between voltage and current. The law is expressed mathematically as:

V = I * R I = V / R R = V / I

Where V is voltage, I is current, and R is resistance. Ohm’s Law says the voltage across a resistance is proportional to the current flowing through that resistance.

Also see our calculator for Ohm’s Law Calculator for High Voltage Testing.